I just ordered the Expert. Guy at Dirt Merchant said he prefers the Expert over the Pro due to the extra oil volume. The Pro looks like you get more clicks of LSC though, according to the setup guide.
Damper on the Pro and Expert are the same. The pro has a sealed cartridge rebound, whereas the expert has an open rebound. Not sure what the Dirt Merch guys are telling you...
Regardless, great feeling fork and I'm sure you won't be disappointed!