I went to see Feist here a couple of months ago and the show was absolutely amazing. This place is much much smaller than the ACC or the Skydome but I think that's what makes it so fantastic. If you're lucky enough to get a big artist to perform in a small venue, it makes the show that much better.
The atmosphere is very warm and intimate - people are quiet and sitting down and really enjoying the music for it's artistic value. I got the sense that I was in her living room just watching her jam on her guitar.
The venue is steps away from Union station, there are several bars located on the top and bottom levels of the Sony Center. It's also right next to the esplanade, which means there are tons of great places to grab a drink after the show.
If you can see an artist or performer here, I highly recommend it!