I just got the notification. I am always wary about doing this. What seems to be the consensus regarding performance, battery life and stability for Nexus 5 users?
Honestly I have more to lose than to gain from this update, I'm quite happy with how my phone is working.
I did a fresh install using an image, but for me: -
Performance - Great. Everything is super smooth.
Battery life - To be honest, I don't think it's any better than it was before. I got a full day out of it before and I'm getting the same now.
Stability - It's been fine for me. The only issues I've had are 2 apps (Mixcloud and an old game that hadn't been updated for over a year) that are seemingly incompatible and crash as soon as they're launched. I made the devs aware in both cases and they're working on fixes.
Obviously YMMV as you're doing an OTA update, but hopefully you have the same experience as me. I'm loving the update and the 1 change I don't like is that I can no longer put my phone into silent mode (i.e. no vibration or sounds) using the volume controls, as now when the volume gets down to zero it goes into vibrate-only mode and there's no option for 100% silent.