EVE blogger, Drone Bay podcast co-host, and former Massively contributor CrazyKinux covers many of the bases, noting many of the strongest differences (skill-based instead of level-based character advancement, everyone is on one server instead of scattered between hundreds of small servers, etcetera). He also links to several articles written by him and others that are helpful to newbies.
It's a fantastic post -- a perfect starting point for anyone considering the switch, or even for folks just curious about what EVE is all about. CrazyKinux ends on a pretty funny quote, too: "EVE is like a sandbox with land mines. Deal with it." But don't let that scare you. Really. We named it our #1 Sci-Fi MMO a while back; admittedly that's not saying much, but it ought to count for something, right?
