Background
I picked up a lightly used MP3 from a fellow MVer a little over 2 weeks ago (thanx, Casp!), and have been enjoying her immensely. Previously, I rode a Piaggio Fly 150, and before that a Yamaha Vino 50, both of which I no longer have in my stable, but have throughly enjoyed them as well.
First Impressions
Prior to the purchase, I have already briefly ridden the MP3 before. Its capabilities impressed me, but the test ride was much too short to get a good idea of the trike could do. Having logged a good 6 or 7 hours worth of riding over the last two weeks, I've come to form a better idea of the capabilities of this scoot.
Two of the very first impressions that I had about the MP3 were its smooth and willing power plant and its hefty weight. I don't know whether the smoothness is inherent to the QUASAR engine design, or whether it had more to do with fuel injection being used instead of having a carb, but starting the scoot is always a smooth, easy, and trouble-free operation, and throttle response seems to be more immediate compared to the carburated scooters that I've ridden in the past. In fact, throttle response in the MP3 is noticeably better than the BV250, which had same engine in carburated form.
Having owned smaller scoots before, the MP3's QUASAR engine gave me quite a different experience. While my old Vino's little 50cc absolutely loved to rev, it was totally gutless even when it was screaming at the top of its lungs. The Fly's 150cc LEADER engine had waves of torque to tap into, but it felt somewhat lazy as the engine seems to prefer riding that fat torque curve instead of working harder and faster. The QUASAR engine in the MP3, however, seems to combine the best of both worlds from my two previous engines. On one hand, it is sufficiently torquey that I don't need to rev the bejesus out of her to get the scoot going. On the other hand, she is willing to play if you want to make her sing the high note. In fact, at first I had to be careful with the throttle to not send the engine screaming to 9k+ rpm.
Unfortunately, despite the willing engine, the MP3 is NOT a fast scoot by any means. She has no problem out-pacing the cagers off the line, but despite the 100cc advantage, she seems no faster coming off from a dead stop compared to my old Fly. Coming off a complete stop, or even from a slow rolling start, I really felt the weight of the MP3 holding herself back. I wouldn't say she is slow per se, but she is definitely not a fast scoot.
The Forte
Right from the very start, it is obvious where the MP3's forte lies -- with the extra contact patch and the fancy front suspension, the MP3 was born to be an apex carver. And on the front, she totally delivers.
Even without carving curves, the MP3's ride quality reminded me of the difference between driving a Japanese appliance car and a Bavarian propeller blade sports sedan. The MP3 is responsive and communicative to its rider, and body motions (of the vehicle) are very well-controlled. Unlike Jess, I was never confused about how much I should lean into turns -- rather, it was always a matter of how much I dared to lean going into turns. The MP3 just does what it has been told -- you lean a bit, and she gives you a bit. If you lean like a maniac, she'll carve the turn like a maniac as well.
One of my favourite manoeuvres on a bike is to do the continuous zig-zag -- on an empty stretch of road, I just keep weaving the bike from side to side, leaning as much as I can in each turn without wiping out. In doing this move, I have never leaned as far and had as much fun as I did doing it with the MP3. With my previous scooters and the few bikes that I've ridden, the transient movements have never been as confidence-inspiring as what the MP3 offered. The scooter was so sure-footed and well-planted that I felt there was still leaps and bounds of room to be explored even when the center stand was already scrapping.
This could well be a false sense of security, as the MP3 may in fact topple over if I lean any further. But that's how I felt on the scoot, and she never even hinted that she'd let me down in a curve.
In my post-ride examination of the tires, I found the best evidence to my most aggressive rides yet -- the tires were worn almost entirely across the width of the tire. In my aggressive turns, I have only left around 1/3" to 1/2" worth of virgin rubber on the outsides of my front tires. I don't remember how far I've gone with my previous scooters, but I know it wasn't anything close to what I did with the MP3 -- and I've scrapped the center stands of my other scoots as well.
Given that the MP3 is such a heavy scoot though, she really makes her weight known when I take her into a fast sweeper. Of course, that's where counter-steering comes in, and I totally felt like a hooligan cranking the handle bars / steering column while I leaned way out.
She's a Big Girl
Unlike Jess, I found the MP3 to be a big girl. Of course, she is not Amazon-sized, but she is definitely not small. I keep thinking that she has to be bigger than the GTS because she's got the rear end to prove it.

(And obviously, she is much heavier as well.) And at 5'10", I found her to give me the perfect amount of room -- even the 2-tiered seat placed me at the perfect distance from everything. I took this as the divine sign to mean that me and the MP3 were meant for each other right from the start.
One very interesting thing I found with the MP3 is that because of her weight, I actually have to put in quite a bit of effort to steer her during my aggressive curve carving and zig-zagging. The direct result of that is, after a series of turns and zig-zags, my waist, lower back, and butt actually get tired from all the effort that I have to exert. Perhaps this is only happening because I was curve-carving like a maniac. Or perhaps it was because I am totally out of shape.
The Balancing Act
In a strange way, I found the balance of the MP3 to be practically perfect and yet completely deceptive at the same time. Because of the front suspension, the fore-aft balance of the scoot is infinitely better than that from any other scooter. In fact, I like the front-rear weight distribution of the MP3 even better than the distribution you get from regular motorcycles -- the front end of other other motorcycles / scooters feels too light by comparison. Of course, this my personal preference, and I can see how the heavier front end could prove to be a challenge for our smaller ladies. But I have absolutely no complains about this -- it is just how I like it.
As Jess has pointed out, the deceptive part about the MP3's balance has to do with its side-to-side weight / balance. It seems to me that up to a certain point (with a small amount of leaning, that is), the MP3 is perfect happy to mask its weight by staying upright more or less on its own. If you are not careful, however, the scooter leans further and suddenly loses all of its will to stay upright. If you are caught off-guard by this, you will most definitely dump the scoot. This is something every MP3 owner needs to be aware of, so put that suspension lock to good use.
High Speed Riding
In putting my MP3 through her paces, I've also done a fair share of high speed riding (nothing crazy -- just up to 110 or 115 kph-ish).
My initial impression of the MP3 at speed is that it is extremely stable. Certainly, this has everything to do with its 3 contact patches, the well-sorted out suspension, and the scoot's heavier weight. At the same time, however, my standard up-right riding position on the MP3 also made me and the scoot prone to cross winds. In fact, during my first high speed run, I was so surprised by the amount of cross wind hitting me that I backed off on the throttle as soon as I had the chance. It took me a while (a good 15 - 30 minutes?) experimenting with various seating positions and foot placements before I found a comfortable and stable high-speed riding position -- I seated myself at the higher passenger seat, and rested my foot on the passenger footrest while bracing the seat / underseat storage compartment with my legs. I also tucked myself in so that I was more or less riding in a typical sportsbike riding position.
Since I am fairly light (only around 135 lbs + gear), I feel like the scoot still has plenty of umph left at 110-ish kph. As long as I am tucking myself in, I think I should have no problem breaking Piaggio's claimed top speed of 125 kph.
Summing It Up
Ever since the Moto Piaggio 3 has been announced, I was thoroughly captivated by the idea of having that extra wheel and still be able to lean. As it turns out, other than the weight, the MP3 is everything I have expected it to be, and then some. Having ridden the MP3, I honestly don't think I can ever ride another scooter / motorcycle with nearly as much fun. Unless that other scoot also has 3 wheels and is much lighter than the MP3, of course.
-Rick