As others have said, if it's a ride I like and I like the design, I'll buy it. The only exception there is my Smiler T-shirt (hell, I'm wearing it as I type this), I don't really like the ride but I really like the ridiculous logo. The shirt just has the classic smiley face and "The Smiler" underneath. Simple design, although the logo is a bit in your face. I try to avoid shirts that include statistics, but admittedly a couple of mine have them (Skyrush, Phoenix). Some of my shirts have cool designs that incorporate the coaster itself (i.e. Phoenix, Maverick, Voyage shirts), but sometimes all you need is just the logo and it still looks nice (i.e. Boulder Dash, Smiler). No way I would ever buy one from Six Flags though. Never been a fan of their logos and I don't want to walk around with a Superman or Joker anyway.