For browsing a forum it's a no-no, as opinion has showed. However I have already found a good use for the new layout!
You can browse multiple messages from any user (including yourself, sorry I mean myself in the 3rd person) to locate text in a thread where all the headers are typically the same, because no one who responds ever changes them (except me and sensible people in this forum of course, lol)
So if you are looking for a way to find your message that says "I love twinkie bars, they are so healthy" under a header which you can't remember, eg "Re: My brother ate my pet frog", it IS now possible. Here's an example I prepared earlier: //www.curezone.org/forums/s2.asp?f=762&ob=d&c=0&t=150&m=Webmaster (well, I had to choose someone as an example, so it may as well be the Webmaster!)