I use Sonar and Nuendo. I love them both. Sonar is very strong in certain areas. Obviously Sonar is a a great MIDI sequencer and editor. What is less known is how strong it is for audio, editing, etc. I do not have Sonar 4 yet, but I am looking forward to exploring it. I would say Sonar is easily in the category of Cubase for audio, but Nuendo is a different notch up due to all the powerful options. I guess Cubase is identical to Nuendo in many ways, but I have not messed with it much. I do not think PT is as good as any of them, quite frankly.
If you do any MIDI sequencing, then definately consider trying Sonar. If you are solely doing audio, I would save more and get Nuendo.
