The Pod I tested through a valve amp using a £2k Jem and nomatter what I tried it sounded harsh, thin and tinny. The GT8 however, I played through a £200 SS amp and it sounded full, beefy and rich just in the few presets I tried out. I probably played for an hour on the Pod and 10 mins on the GT8 because it was obvious from the first 10 seconds that the Boss was better.
Now, I know you might say that it takes time to find a good sound and I should give the Pod more of a chance but I couldn't get anything remotely good in an hour, whereas the Boss sounded good straight away so it could sound phenomenal after some deep tweaking.
I also liked the layout and use of the Boss better, there was much quicker access to everything and it seemed more logical. It also has better features imo with the dual channels and solo boost etc..