In regards to performance, for whatever reason, IE is still doing s better job rendering webpages than canary for me. Specifically web apps with heavy amounts of rendering work much better in IE than Canary for me still.
Canary in metro looks very sharp and clean, that problem I had with Firefox. Pinch zooming is also really smooth and quick, also really easy to pinch zoom-out back to 100% (doesn't zoom out further than that).
I love the TouchMe gestures, but I'm really happy that Canary has that built in too. Shows that Google is putting more attention towards touch-based optimization.
I agree, pinch zooming in Firefox should be better. It actually changes the zoom level setting of the page, and as you said it doesn't stop you from pinching out further to be less than 100% zoom level.
So with Canary, you didn't have to go to Compatibility Tab -> "Disable display scaling on high DPI settings", and toggle some chrome://flags such as HiDPI?
I'm with the other cat... Chrome Canary is VERY slow in Windows 8 Mode for me. Furthermore, whenever I relaunch in Windows 8 Mode...Hangouts stops working and I also cannot seem to reach the Chrome Web Store.