I never ran the pod through anything else, but it help add that tube tone. As for coloration, when running the pod through the amp with no modeling at all the thing is crystal clear, very clean.
I always play it with volume right around 1 with distortion, and channel volume 3/4 to max. When playing clean you can turn it up louder, maybe to 2. Tube amps are really loud, but so is my 5 watt epiphone valve jr.
Just about all tones are good, but they will take time to tweak unless you find some good patches. I actually decided to sell mine as less is more for me, I spent more time messing with everything than I would have liked. Meaning clicking through my tones. As I said it has a booming low end, which is good if you want that, but it can be dialed out. Also some say that it is dark sounding, which I think is a reference to the low end.