Just a couple of observations ... it seems to be getting fairly stable now, though who knows what changes will happen between now and the final release.
One little irritation involved gamin. I had to manually add a gamin config file
otherwise Konqueror wasn't showing files made (or deleted) until I hit refresh. Took me a couple weeks to figure that out.
I've heard that the upgrade to gcc 4 (4.1.2) may cause some problems compiling some things, especially games.
I haven't really noticed much, in the way of newer stuff, that I miss in VL58; but then, I'm not running Beryl etc. I could have missed something, especially related to xfce, as I've only used KDE (3.5.6 and now 3.5.7) in it, and have spent a lot less time in Slack than in VL. (I don't think I'm quite cut out to be a true Slacker ... I installed slapt-get and the tukaani package tools with lzma early on
Agreed that performance with stability is one thing that makes VL great!