Which ride to buy
I'm not a high miler compared to many in this community, but I did put 10K on an '07 250 GTS and now have just shy of 5K on my '12 300 GTS and all I've done is change oil, one CVT belt on the '07 and a couple back tires. There's a huge difference, in my mind, between the 250 & 300 in the gitty-up department. If I crank the 300 from a standing still position the front end gets light real quickly. I don't go there often but it is a bit intoxicating...for a scooter experience. I find the 300 much smoother too at speed than the 250. I haven't ridden any of your other choices but I don't think you'd be disappointed with either model Vespa.
My riding is primarily on the secondary blacktops but it's nice being able to hit a freeway if time ran away with me and I'm heading home.