What do you mean? Read their feature list, they are two different products. You would hopefully choose the one that best suits your needs.

Simple comparison chart...
http://www.motu.com/products/motuaudio/compare.html/en

I've used the original 828 for years and it's been okay. I realize things may have improved, but the preamps kinda suck, and the converters are just alright sounding. You get what you pay for. IMHO, you could do much better with an RME Multiface w/ card-bus option, for almost the same amount of money.

Depends on the type of firewire you have. the Traveler requires the six-pin connector for bus power.

If you are on a mac no problem with either.

8)

Off the top of my head, it seems like with the Traveler you're paying for the two extra pres and the 192k option. If you ask me, I don't need either of those things. I'd rather spend the extra 2 bills on a better outboard pre. Plus, the 828 is rackmountable out of the box. I got one of those SKB rolling rack cases and I put my 828mkii in there. Now it travels!