I came from stock 4.0.4 with Sense 4.1, so whenever I make comparisons, I compare it to that.
- Stability. I've really only encountered a single bug. That's actually better than stock for me. Definately stable enough to use as a daily driver. I am really impressed by this.
- Speed and smoothness. Everything flows really well, making the interface a joy to use.
- Battery life. For me, it has been notably but not dramatically better. I get about 3.5 h screen time (I got about 3 h on stock).
- The interface. Everything is prettier than Sense. I could never go back.
- The settings. The number of settings isn't as large as CM7 (which was a bit insane), but larger than stock. You can tweak more or less everything you care about.
- A bug making volume wake unreliable. It's on the tracker: http://code.google.com/p/cyanogenmod...detail?id=6720
This matters a lot for me since my power button is quite unresponsible. But it probably won't matter to most users (although I'd argue that waking the screen up with volume buttons is more comfortable than the power button)
- While it's great that you can cutomize the lock screen shortcuts, you can't move the "unlock". It's always to the right. You can install another lock screen if you want, though. It's a very minor issue.
- The contacts app doesn't seem to work with Facebook, so if you (like me) get all your contacts' pictures from there, you're out of luck. Slightly annoying. Third party apps like Haxsync can fix this though.
- The timer and the alarm are found in two different apps. And the timer app is a bit wierd, coming from stock. But it works.
- Camera quality seems good enough. Taking photos is really fast, much like stock, but you can't just hold down the button to do burst mode.
- I don't miss Beats Audio. The DSP Manager, an included app, let's you activate bass boost in three different levels. For me, this gives more than good enough audio quality.
A great rom. Don't stay on stock
If you want me to add anything else, just ask