I don't think you can go wrong with the 450i unless your a big dude. My neighbor is 285 and 6'5" and yes the machine is small for him. I am only 5'6" and it fits perfect. Had mine for a year, 440 miles, no issues!. The rear brake disc clatter in reverse is common among all Kymco and other SxS machines. The only complaint on the 450i is the notchy shifter, having talked to the factory it is because they use a spring loaded shift fork so it can be tricky shifting gears getting out of and going into but you get used to it rather quickly. The factory is having a 1.9% finance program going on for 36 months....cant beat it. That is what I bought mine under, but paying double payments so it will be paid in march 2017. When riding in a large offroad gravel pit a couple times over the summer and had no problem climbing any hills I wanted to climb, even pulled out of the mud a RZR...bot was he surprised at my Kymco! Tope speed is set to 48 mph as the rev limiter kicks in then, I am told it is the same for all the UXV models including the 500 & 700. I do know the 450i will beat a 500 in a drag race right up to about 40 mph. Overall I am very pleased with my machine and more and more after market stuff is coming out everyday, they are that popular. The scaled down size I think is a really big factor in the 450i, some of the SxS machines are really big and I find the compact size to be an advantage. Keep us posted on your findings.......