I compared the J-Station and POD to
the SansAmp PSA-1 and I ended up taking the SansAmp home even though it cost considerably more. I've never used
the GT2 but it's similar technology. When I compared the different units it was through headphones and a P.A. and the SansAmp sounded more like the tube amps I'm used to playing. It has one sound really, just like a real amp. The modeled units like the POD do give you a variety and that might be beneficial in the studio. I think that all these modeled simulators will get even better in the next few years, more programmable, better effects. I hope they also go in the direction of the Roland VG series, synth type sounds and unique creative other-worldly sounds.
I usually run floor effects in conjunction with the SansAmp. Chorus pedals, delays, flanger after the pre-amp. If I'm playing distorted leads I put an old distortion pedal before the SansAmp.
When I play live in my bedroom or with friends I only use a real tube amp with little or no effects....I'm kind of a traditionalist in that regard. ( I use
a Peavey Classic 50 ) Guitars and amps haven't improved that much in the last 20 years, that's why people still play Les Pauls, Stratocasters, ES-335's, Fender Twin Reverbs etc. You're SansAmp looks like a dinosaur considering all the new things coming out but in fact it's trying to duplicate sounds that have been around for years and will probably never go out of fashion.
Bottom line..if you wait one or two more years there will be amp simulators on the market that will blow away POD, SansAmp,
Ampfarm, J-station. We haven't seen anything yet.