The answer to your question depends on your individual needs. Yes, 10512 is better, but it might not be strong enough for your primary phone. I had it installed since release and just reverted my Lumia Icon ( Verizon ) back to 8.1. It is a secondary phone for me, but the problems were still sufficient for me to finally give up on it a few weeks later:
There is a sufficient lag time with most apps, including the login screen. It is just downright slow in all aspects.
Bluetooth issues are not resolved, and it is very sketchy with the Microsoft Band. Communicating with Cortana via the band does not work at all.
Voice activation is not working on my phone, and thus, no "Hey Cortana"
Email is annoying because we cannot unify multiple accounts into one inbox as we could previously in 8.1.
There are still many problems with the Store which means updating of primary apps is sporadic.
Call quality seems to be OK but more than once I lost a call when trying to answer it.
Messaging seems to work OK for me, but apparently not for everyone.
The Verizon Visual Voice Mail app does not work, at all, and thus that service is not available yet.
The photo app is confusing, and photos do not seem to be uploading to One Drive as they should. I simply can't depend on the camera yet although it is the best camera phone I own.
So ... take a look at all the comments and ask yourself "Are there issues here that will regularly annoy me. If so, it's not the update for you.
Tim