i use GR3 and Amplitube 2 (with Fender and Bass packs thumbsup)...I recently started using "Recabinet", which are hi quality IR samples of classic amp cabinets (in Logic i load them into Space Designer).Recabinet makes Guitar Rig (in particular) MUCH more realistic and useful...Now, i run GR3 and and bypass the preset Vox cab, instead using Recabinet's vox cab...RC makes GR3's cab models sound horrendous in comparison and it's CHEAP! Improves some but not all of Amplitube's presets as well.
Recabinet - Album quality guitar tone, direct. Speaker cabinet impulse responses.
I'm also preordering Amplitube 3...