YVR - Never had a problem myself despite many trips as an East Indian male inbound from Asia, but have heard enough horror stories and have had employees misconnect a few times thanks to delays in secondary that they rank near the bottom of my list.

YYZ - Usually very businesslike and occasionally even friendly. Been sent to secondary more times than I can remember (mainly 'cos I use it more than all the others put together!), but never been delayed beyond a few minutes. As long as everything is in order, processing is always quick.

YUL - Not very friendly. Bottom of my list. Virtually always get sent to customs secondary, but rarely any delays. The facility is a dump though, so maybe the crappy ambience plays a part.

Other POEs have too small of sample sizes to be particularly relevant.

As for the US PFI facilities at Canadian airports, the less said by me the better.