I haven't updated my Nexus 4 to Android 4.3 just yet, but it looks like those that have are finding issues with the latest update. Some users are reporting overheating, rapid battery drain, frequent crashing while in use and a perpetual loop during boot which renders their Nexus 4 unusable.
Other users are reporting that their Nexus 4 has become too slow to be usable. There are other reports from users that state passwords not being requested, which prevents their Nexus 4 from being unlocked. Whereas some users are reporting that there is no multitouch capability, reception issues, data disappearing, and applications that have gone missing.
The bad news for Android 4.3 on the Nexus 4 doesn't end there, with other users reporting that a device erase and factory reset fix the issues, but users shouldn't have to resort to formatting their phone to resolve an OS update problem.