A root exploit for the GB update will be found. There is no telling how long after the update it will take for it to happen but the dev community will find a way to root it, I wouldn't unroot to get the GB update because who knows what HTC and VZW will do to screw it up, and like I said before there will be a plainjane rom right after the update.
there will prolly be a plain jane out before... id be really surprised if it wasnt leaked prior. and like yeahha says,it will be just as good as the OTA. it actually will be the same code as the OTA,with the exception of not having a stock recovery or hboot.
i just dont understand why people are so hard on the current GB sense roms. seems lots of folks have forgotten that the roms we have now are the amazing work of amazing developers despite the fact that they are using a buggy pre-alpha leak as a base. they have done an excellent job of fixing alot of the bugs and issues,without kernel or source code.
when the OTA rolls out, the GB roms will have that as a base,and all custom roms will be super smooth and polished,just like current froyo roms.
when you accept the GB ota,youre gonna reboot your phone and find no 3.0 lockscreen,no other 3.0 eye candy... no tweeks... just a rom that looks exactly like your stock froyo rom,with the exception that in "About phone" it will say "2.3.4". and they youre gonna be stuck with that while the rest of us who are patient and followed advice from the root community are enjoying the crap out of stable,polished,smooth custom GB roms with sense 3.0.
for what its worth,the evo guys havent figured out a new exploit yet,and they got their OTA right after we got our first leak. the only option thus far is to use the RUU/installer to roll back to rootable froyo. so if you unroot and acept the OTA,better keep you fingers crossed that the same thing works on the TB if you have hopes and dreams of rooting it again someday.
please note: the above is not directed at yeaha. i know he and i are on the same page.
once again,my 2 cents