Interesting thread. My everyday ride is a Vespa GTS 250 and I also have a Triumph Tiger 800. I've had 2 or 3 other scooters and a selection of Honda and Ducati motorcycles over the years and I can say with confidence that the Vespa is my all time favorite daily ride. With a Givi topbox I can fit a week's worth of groceries or use the bike for riding into downtown Denver and parking just about anywhere.
While I love the Vespa, I have not been able to find a real maxi scooter that I prefer over a motorcycle. The T-Max comes close as do the Piaggio and Aprilia 500's, but I'm not sure the latter 2 are really maxis. I'm hoping the new BMW's do the the trick but right now I'm still very happy with the Triumph.
I think most of the positives and negatives have been covered already. The only thing I'd emphasize again is that the standard scooter riding posture isn't always comfortable for long stints in the saddle. You need to make sure you're actually comfy on whatever scoot you decide on. It helps if there's room on the floorboards to move your feet fore and aft. It also helps to take a long test ride. Good luck!