I recently made the leap from Sonar 6XL to X3 -- with much foreboding. Some of the problems floating around the forums about X1 and X2 made me worry that Cakewalk/Roland had gotten off track, but I was having serious problems getting Sonar 6 to work on my new PC, so I took a chance.
Turns out, it went pretty smoothly, from the install to first use. In fact, I was able to complete my entry in an contest from beginning to end in just a few weeks time:
https://www.indabamusic.com/opportunities/zz-ward-365-days-remix-contest/submissions/3b23fe0c-6114-11e3-a284-12313b020cf1 Everything but the vocals on that track was done in Sonar -- keyboards and horns in Dimension Pro, guitar with Goliath, etc. For a weekend warrior that usually has just a few precious hours each week to focus on a DAW, it was refreshingly efficient.
I still have a technical glitch (uh-oh, thinks tech support) with the audio engine quitting randomly, but I think I can fix that given the number of times answers have been presented on these forums. I just haven't taken the time to do the knob-twisting.
Anyhoo, bottom line is it looks like X3 is solid, and any lingering 6XL holdouts might take this as a word of encouragement.