I think the update is called GDR3, but I am unsure. I am currently running OS version 8.0.10327.77. I have a Windows Phone HTC 8x with Verizon as my carrier. I just downloaded and installed this update yesterday (new features listed here: http://www.windowsphone.com/en-US/how-to/wp8/basics/windows-phone-8-update-history). Of course, being part of Verizon, I was excited to finally use group texting and I liked the radio feature and Google account compatibility assurance. Though all of those work well (I am assuming), there are now new problems that were not issues before this update.
First Issue: "Can't send message. Try again."
As seen in this image:

No matter how many times I hit try again, it does nothing. I can copy and paste the text and it will result with nothing. i can try to type a completely new message and nothing. When I get these texting "blocks", it isn't just for one contact but all of them. It has nothing to do with reception or internet as I am in areas with strong reception and access to both. This texting failure would never happen prior to the update and it is quite frustrating that it now does. This error only happens when texting, but if i switch to Facebook it works completely fine. However, I don't communicate via Facebook and neither do my friends. We text and right now about 50% of my day results in failed texts.
2nd Issue: Slower phone
Everything my phone does is now a second or more slower. Open texting, email, an app...whatever- it all takes longer to do and is looses its fluidity it had before.
3rd Issue: data operations don't work as well.
Anything using data when I am away from wifi either fails or takes exponentially longer to use. Internet browsing is agonizing now when I need directions or quick answers. This may in correlation to issue #2, but I am certain all of these are related to the overall new update.
Please fix. I love Windows Phone when it works, but with the bugs and "late in the game" on apps and features that are staples on Android and IOS devices, it sure makes it difficult to be a Windows Phone fan. I want to be able to brag about my Windows Phone with anyone/everyone so they will want to get one too.
FollowrOfChrist