Just to give my own POV, having owned the 2004 Vespa GT 200 in the past. I should first add the caveat that the Vespa was my first scooter ever, so things like sentiment and rider inexperience may contribute to some of my impressions. I mean, heck, someone in Bajaj beat me as a newbie Vespa rider, and people often say Bajaj's are slow. But having said that, I think while some things can be improved with rider experience, like fast acceleration, handling, etc., some things, like top speeds, should stay the same regardless of rider input.
I'm inclined to say the Blur is better balanced and handles better. I feel like the Vespas are a tad rear-heavy (I feel this effect even more exaggerated in bigger scooters with a similar structure, like the Piaggio BV500.) The Blur is also leaner/narrower, so in California where it is legal to lane split, I have more confidence with the Blur than I had with the GT. I've taken the Vespa on the highway a few times (once on an 80-mile run through Marin), and I don't think it ever went much past 70mph (indicated on the speedo), although this depended on the winds - against a strong head wind it would dip below 65mph at WOT.
Having said that, I think the modern Vespas are well-built and have a comfortable, friendly feel to them, and they are fun to ride, probably at least in part due to the small 12" wheels that gives you more of a gliding feel in your ride. Despite the niceness of smaller wheels under some circumstances, if maybe they'd move the 250cc model up to 13" or even 14" wheels I might go back to a Vespa one day, because 12" can feel a bit small and uncertain on uneven or slippery surfaces. You do pay a premium on a Vespa (compare e.g. 250cc GTS vs. 500cc BV500 with a small price difference between them), but it's not just a brand name factor, I think they are very nicely made (although not perfect, as no scooter is - e.g., why don't they come with side stands? They are convenient for mounting and dismounting, especially with a passenger), and as they do have the brand name factor, they do better at resale than really any other scooter currently on the market. That's a very good thing, especially if you like to switch rides every year or two for variety, which I do.
I eventually sold the Vespa so I could get the BV500, with the idea that I could feel more stable at highway speeds and I am not WOT when going at highway speeds (nothing to make you feel limited than when you first try to catch up to the car before you and twist the wrist, to find... hey, no more throttle left). Buying the BV500 did accomplish that goal, but after the initial power rush I found that it was less fun than the Vespa at most speeds I was usually in, which are street speeds, not highway speeds. Which then made me start thinking of buying a smaller scooter for city activities. Which leads me to the Blur...
Well, what can I say? I finally realized I don't really go on highways all that much to need a bigger scooter. So I sold the BV500, and on occasional trips across the bridge (45mph limit), I do just fine on the Blur, even with cross winds (I have a windscreen and I tuck my body in - also I usually don't have my big Givi back case then, because that can affect that scooter at street speeds, the way the case catches the wind). At this point I've owned the Blur as long or longer than my other scooters, and I'm perfectly happy with it, other than a) lack of glove compartment; b) some lack of oomph (seems like that's the biggest gripe among Blur owners, besides rider ergonomics which depends on the rider); and c) unexceptional resale value (or so I imagine, since I haven't tried and don't see ads for Blurs here in the Bay Area, where scooters seem to get advertised at higher-than-KBB prices on craigslist, whatever the actual success rates for sales may be).
Having said that, if I had kept the Vespa all this time, would I still make the choice to switch to the Blur? Considering the expenses involved in switching, I'd say no, unless change for the sake of change itself was all I was looking for. They are similar enough in cc's and handling, storage, etc., that I don't think there's a big switch. Having the BV500 between the Vespa and GT has made each scooter switch significantly different for me. By comparison a Vespa-to-Blur switch would be too subtle to go through the trouble and expense of taxes, registration, abandoning any upgrades made to the old scooter, etc. Of course, we know at least one rider who has found the difference significant
so the old adage of YMMV applies as usual.
So I am satisfied with the Blur. But a scooter-holic's never done... Now I'm thinking back to bigger scoots, like a Yamaha T-Max, or an Aprilia Mana (ok, technically an automatic motorcycle, but same idea) - but jeez, at those prices maybe I might as well just buy a car... But regardless, I plan to hold on the Blur, at least give it a season or two to compete against the new ride (I guess one thing about having low resale value is you're not that worried about having to sell right away to get that higher resale value - it's gonna be low regardless of when you sell). One thing I like about scooters is the idea of economy - gas, parts, size, price, etc. - even the part about not having to buy (or wear) a backpack for shopping, because of the built-in storage space
