I'm running it on a 1320. So far so good, although it did take 3 attempts and a boot loop! Took an age to install, but we'll worth the effort.
Runs quite well on the old girl. Very little / negligible lagging. No resuming issues. Looks nice on a huge screen. Battery drain is on a par with 8.1, which surprised me. My only issue is store downloads take an age. I end up killing WiFi then reconnecting, and away it goes. Edge is pretty quick as well. The Fitbit app was up and running in no time. Bluetooth picked up my flex straight away.
So far so good. It actually feels like MSFT are getting somewhere. This is a huge improvement after the last build, and it seems to have hushed some of the haters, which is worth it on it's own.
These are my own opinions, and are therefore, subjective.