Foy's (our resident Solarforce king) review of the Solarforce L2N. I really like the style of the L2N (though I'd prefer a reverse clicky - solarforce sells the switch guts to convert it too). I still haven't ordered one myself.
I usually hear that the Solarforce drop-ins aren't that great, though I think the newer XM-L U2's have been decent.
-Garry