Unless they fixed it, and I haven't heard any word that they have, I think the most complained about issue is that contact information is not working in the stock messaging app. For example, if someone that is in your contacts texts you, it will only show their number, like they're not in your contacts. This doesn't affect 3rd party messaging apps, though.
The contact/phone number text message issue is not a big deal. It happens every once in a while. Usually closing and re-opening the messaging app fixes it. Certainly isn't worth not updating over. As others have said... third party text app don't seem to be affected.