pencilartist
I'm using Bias and Bias FX. Love them both. I also use GTR3 and GR5. TH2 was always a disappointment for me, but TH3 looks much better.
GTR3 is one of the ones I keep, not that it can compete with BIAS or TH2/3 in my opinion, but because when I use it and have a certain sound going on, and it inspires a song, no matter what other amp sim I try I can't replace it for that song. Never liked Guitar Rig, it just sits there unused.
If you had TH2 that was included in Sonar, and not the FULL version, that could be a reason for your disappointment, and perhaps the GUI. The GUI never bothered me, and I spent a lot of time getting to know TH2 and how to get what I want out of it, and for me up until BIAS Amp Pro and BIAS FX Pro, TH2 was my favorite by far. I pretty much own most major and not so major amp sims out there, and for me BIAS and TH2/3 are far above them all (yes including S-Gear2 and Amplitube 3/4) I recently traded all my Amplitube gear, Amp3 and Amp 4 and all things available in the custom shop for some Toontrack gear.