If you just want to use it for effects, and not the amp modeling, either would be fine if you run it in the effects loop. The Boss would probably be better for this purpose. I've used my XT like this, and it sounds pretty good. I use regular pedals 99% of the time though, because they just sound much better.

@6strngs... I wasn't trying to rip on you or anything. I defanately understand about the price. I doubt you would be able to tell enough difference in tone between the two to matter. Unless you've been around amps a long time, played many amps, and have learned how sertain things effect tone, the difference will be neglegable.