Basically, bugs are found much quicker when a wide variety of users test it out. It's definitely not for everyone but those that like to track things down and report what doesn't work properly really help out. The same set of eyes will sometimes miss some things that a fresh pair can spot easily.
A couple things though. UBB.threads doesn't have a display name / username at this time. So, that's just normal behavior as always. Some of the others you pointed out I was not aware of so they still need to be fixed.
As for is this going to go on? Perhaps, but I can't say for sure as to how long. Normally the betas go pretty quick but this was the largest upgrade to the scripts yet. So there are probably other bugs that haven't been spotted yet.
So, I would say that if you are on any type of timeline then you should probably go with 5.5.1. []/forum/images/icons/wink.gif[/]
