S-Gear is right near the top of my list (I might still slightly..and I mean SUUULIGHTLY) prefer Amplitube 3...but there S-Gear is nose to nose with it...and in some cases superior.
 
20-25 years ago, I NEVER would have believed you could get sound like that going direct in.

Over the years I picked up a few different amp sims ....Guitar Rig, Amplitube, Amp Farm....ect. they are all excellent. They all have highly usable amps, effects and presets....but something changed when I bought S-Gear. It just became the easiest one to usez and it sounded the best in my projects....I only use the others when I need a completely different tone or they have an effect like auto pan, that S-Gear does not.
 
I think in general we gravitate to what works well for what we do...when S-Gear started out they only had 4 amp models, they have since added more and broadened their audience. They did the same with effects. 
 
That is what a good software company does....