OK, first thoughts.
1) The color scheme is markedly different: the old one was mostly neutral grays and blacks; this one is white on black in a sea of red. I think the red is too vivid and distracting, and would prefer a dark gray, or failing that, a much less saturated red. (I realize there's a sorta floral, vaguely paisley-ish pattern going on.) Also, I think white on dark gray is a bit easier to read, but that could just be me.
By the way, does PHPBB3 have the ability to let individual users select either dark-on-light or light-on-dark color schemes? (answering myself: yes, there's "prosilver". I might just use that.)
2) Functionality. I admit I don't remember the old version very well because I've been on this board infrequently, but I miss handy features like "quote this post", "quick reply", "edit this post", and so forth. (Interestingly, they're still available in the prosilver board format.)
2b) I kinda like using BBCode; is there a reason it's been turned off? Is it due to the board style?
3) alternate styles: bmiles3 looks easy on the eyes. The only thing elementRed has on it, in my opinion, is that elementRed works better for wide browser windows because it forces the forum into a narrow column down the middle.
Also, eMuza2, Serenity, SoftBrown, and Transparent all look kinda nice.
http://www.phpbb3styles.net/db/style/bmileshttp://www.phpbb3styles.net/db/style/eMuza2http://www.phpbb3styles.net/db/style/Serenityhttp://www.phpbb3styles.net/db/style/SoftBrownhttp://www.phpbb3styles.net/db/style/transparent