I use Cake 9 synced with Samplitude Producer, and I agree with Fats on the "kludge" factor, especially the digital audio portion of the program. Cake's MIDI implementation is pretty straight-forward, the editing is easy.
The reason I use both Cake and Samplitude is that Cake still hadn't figured out what digital audio was by version 9. I have Sonar, but have yet to load it since the virtual synths take more horsepower than my old DAW has available. I'm going to be building a new DAW this winter, most likely two separate P4 machines with one dedicated to virtual instruments and MIDI, the other to audio recording, at which time Sonar will be the main program on the synth machine, samplitude the ONLY program on the audio machine.
Soundwise, even at only 20 bit in, 32 float til burn time, Samplitude has never made me wish for better sound. I think they are one of the best-kept secrets in digital audio. Can't wait to hear it with the new gear (re-doing entire studio this year)
Intuitively, Samp is pretty easy to learn the basics, and so far everything I wished it could do was just a menu or two deeper than I'd already been. Some things were too simple, and I felt like a dork when I called tech support and got the answers. (can you say, "Doh!!!")
If you don't need MIDI, or just need to sync (either direction) to MIDI or SMPTE, I would highly recommend Samplitude.
If you're doing other people's projects where you have clients in regularly, the name recognition of ProTools is important. But I've talked to a couple of people who claim they have pro tools to get them in, but do most of the real work with Samplitude because it sounds better.
Just another viewpoint - I'm out in the boonies and do mostly my own projects which I want to sound as good as possible, so I doubt if I'll EVER join the "Alsihad" snobs... Steve
BTW, I tried a demo of CuBase and NEVER could figure out where things were or what they did. One of the LEAST intuitive pieces of sh.. (oops, I meant software) I ever saw...