I haven't tried any shell replacement software for a long time. But I have tried a lot of shell replacements in the past so I'll share my experience .
My suggestion about replacing your shell - > "its not worth it"
Every shell i tried , fell short in some way. SOme didn't have good tray support, some didn't have a proper desktop. I came to realize that explorer had a lot of features that i took for granted. what you can do is instead of replacing explorer use applications that add power user features . like powerpro, autohotkey , autoit, findandrunrobot, strokeit etc .
Kde4 is looking good,,actually my aim is to launch everything from my desktop,like all partition drive with right click file launcher and categorize all my important application