Question. Right now, I just download the Update.zip file for new builds of BB, and install those. What is / How do you use, the ROM (nandroid backup) that he posts in his update post? I heard this is the preferred method of updating.
It's a matter of preference. If you aren't getting slow downs or aren't having any problems, just use the update.zip method.
There are many folks that think you should do a new rom install on a clean system. Some developers feel the same way and only supply their roms as nandroid Restore files. Pete, of Bugless fame, does not share that feeling and in fact he posts both types of files and instructions for each. To each his own.
I've installed at least a half dozen roms, counting updates, and I've always used the update.zip method because, and I know this is a terrible reason, it is easier. I've had no problems, that I know of.