I've been playing with sonar for about a year, and I'm mostly pleased with it, it's downsides are it's unstable, and has lots of bugs that cause CTD's on my system. Sound quality is excellent when it is working right which is a must for a DAW. Usability is not there at all, it has plenty of quirks to learn and is fairly unintuative, even for someone with 20+ years of using DAW's. Drum maps are a real pain in the butt to work with, though it's not forced on you, it does make more sense to me to use one. The main reason I bought this DAW was the fact it's on steam, and ergo I can use it on multiple systems without worrying too much about drm copyright issues expecting dongles ect.. and on that front it works well, except.. some of the added bonus things like Additive drums.. is limited to two PC's... total no brainer there. The community is good and the staff are helpful and know what there doing. Customization is one of sonars big strengths, you can make multiple custom layouts and switch between them fairly easy once you know how to set them up. You can't however remap all the mouse keys very well which is a let down for me who has 4 buttons going to waste. Another sour point is the ACT setup, it's far too overcomplicated and took hours to setup a simple control map for the A-500 pro I have. Poor documentation and too many steps are expected from the end user, I think someone needs fireing for this. A good sound card is essential. You can run it with onboard sound cards, but it's messy and sound quality soon suffers. It's an easy fix though to install a new USB soundcard that are for a good one, as much as a youd pay for a new HDD drive. I don't have all the tech to really make sonar shine, and considering at times I just want to run on a laptop and avoid more tech - this becomes pure hell to work with (who ever guessed I'd miss a scroll lock button). At home on my tri screen setup, it's comfortable and with the MIDI keyboard to help play around with it's going to take me a lifetime to exhaust the possibilities. So not very mobile friendly. The VSTi's are a bit bland, and invoke some of the CTD's that I mentioned. Biggest culprit is Z3ta, with Rapture not far behind. Though the others seem pretty stable.
All in all, I highly recommend this software. It can't turn you into a musical genius, but if you were a musical genius it's got everything you will need.