OSOK, I think both the models you listed above are 250's now. Back when I purchased my TW in 2005, most of the model's were 225's, and I didn't see much of a difference. If I was in the market for a bike today, I would go with a 250 instead of the TW. However, I've been very pleased with my TW as I use it (not a lot of open highway riding...but some).
The TW does have a bit lower seat heigth, but a Yamaha XT250 isn't much different. Saw them side by side at a dealership a couple weeks ago and was surprised the XT was nearly as low, seat wise, as the TW.
Thems my tought's.