I have to agree with Keni re: lanes zooming.
I've been giving SONAR a huge workout lately with a massive track I'm working on. Just zooming in on a vocal track to do comps is annoying for me because you can't actually lasso anything properly - the main track zooms but the lanes don't actually expand when I use the Fit Tracks to Selection workaround that I'm using while the Z-drag bug is fixed.
If I want to expand the lanes themselves, I have to drag the size up of the lanes and zoom horizontally if I want to do any tight editing work, which might actually be for a cross fade or to check to see if a transient isn't being cut off. Doing that with a working zoom lasso is literally half a second's work. This way, it's very fiddly to get it where you want and really adds a lot of time to an editing session for me.
Related to this, lanes in generally slow me down a lot anyway due to how fiddly it is finding the hot spot to change the smart tool, and many a time I'll find that I've muted a lane rather than selecting it, which means even more work. Frustrating. I'm aware I can use the HUD to change tools to fix a lot of those things but that's kind of passing the annoyance from one place to another for me.
This stuff aside, SPlat has been really great to work with overall. Solid and intuitive and is really getting the job done with whatever I throw at it.