I recently shopped extensively for an amp sim, and found that many seem to offer particular advantages that address particular needs.
For example, I currently use
a Roland VS1680 to record, and play guitar and bass live frequently, so a plug-in was not going to be the best fit for my needs. I went to Mars and tried
the Johnson J-Station, the POD, and the Tone Works (Korg)
AX1000G. I was actually very impressed with all three.
The Korg has, in my opinion, some very nice vintage amp sounds. It is warm and "natural," and responds well to volume changes without getting cheesey. And for vintage effects, it is a fine machine. It also has a controller pedal, so it lends itself well to live performances. However, the bulk of my live playing is on bass, so I turned my attention to the other two.
The sounds of the POD and J-Station really knocked me out. I went back and forth for a while. They are both fairly easy to program, and have a lot of sweet presets. Ultimately, I chose the J-Station, because it also has a few bass rig simulators and a couple of acoustic sims (I actually found that the "SWR bass rig" yields a very nice acoustic guitar sound as well, with a little tweaking). For a nice fat distortion, I love the "J Crunch" setting. Best of all, the J-Station was $50.00 cheaper than the POD.
As far as reps are concerned, both get a lot of respect. It's hard to read an interview in "Guitar Player" magazine these days without seeing constant references to the POD, and it was reviewed by GP in the May '99 issue. There is also a very favorable gear review on the J-Station in the Sept. 2000 issue.
I would suggest you try to find a place where you can try them out, if possible, and get the one that works best for your situation and style. For direct recording of guitars, though, I think that you can't go wrong with the J-Station or POD.