The bolt carrier and bolt stays WAY cleaner and cooler. The gas block up front gets dirty and hot. you will need gloves if you are shooting a lot.
i heard a quote someplace that says it well, Piston guns don't crap where they eat!
Check LWRC forums for some great pics. Here is one from this great post, http://forum.lwrci.com/viewtopic.php?t=9721
. This guy takes some incredible pictures. I think he is Stickman on Flikr
Call LWRC they will either sell you one or point you to a dealer with one for sale. The customer service there is AWESOME! There are also a Couple of good dealers on the forum.