I find it mildly annoying that the now time marker in the piano roll view extends all the way down into the controller lane. It means that if you're trying to adjust e.g. the velocity on a note at the point at which the now time marker is set, you cannot see the value in the controller lane because the marker obscures it. 
 
Also, has anyone noticed a bug whereby selecting a note with the smart tool will NOT make the corresponding line turn red? Every now and then I will try and adjust the velocity of a note with the smart tool and I get no visual feedback in the controller lane until I release the note. The problem goes away if I close the PRV and open it again. 

Can't say it's ever bothered me, I'd just move it if it was in the way.  I generally watch the value at the note rather than the controller pane which may be why it's never bothered me.
 
Dan

Like I said, it's a minor complaint. The controller pane acts as a useful visual guide to your velocity values and I guess whether you prefer to gauge them here or by watching the value at the note is personal preference. I can move the now time market of course - it's just a minor annoyance in the workflow.