Both are awsome. What type of riding do you plan on doing? Goofing off around the yard, racing, MX track?
The fiddy is awsome for goofing around in yards, its small enough that you dont need a lot of room to have fun.
The 110 is bigger, roomier, and faster. My guess is it would probably be a little more fun on a dirt track, unless you have a pretty modded 50. You can usually find 50s cheaper, parts are cheaper (depending on what you get) compared to parts for the 110. More parts are available for 50s then the 110s right now.
Im about 5'11 @ 180lbs. I dont have any mods on my 50 yet. A bar fix is in the mail and I'll be getting springs next week. Other then that Im happy with my fiddy.