I like my J-Station, too. I'm a studio musician primarily, so I can only speak about recording, but if I take the time to tweak the presets (using the "deep editing" provided), I can usually find the sound that I want. For $149, the Johnson is a real gem.
When reading product reviews, I've noticed the following trend:
The J-Station is tops (or near tops) for producing clean sounds or a good variety of overdriven sounds. In contrast, some reviewers have felt that the POD beats the J when it comes to producing more outrageous sounds. Since I'm more of a traditional guitarist
(Morse, Howe, Metheney, etc.), I need no more than the J.
If you can, stop by a store and play with it--nothing beats an A-B comparison, right? Good luck, whatever you decide.
J.