I've been a long time Grixis Delver player I haven't really played much sense GP Vegas. I was thinking about switching to Czech Pile for an upcoming tournament but the recent results from Eternal weekend and SCG D.C have me reconsidering.

Grixis Delver is definitely from the Xerox school where as Pile tends more towards midrange. Also Gitaxian Probe is a filthy busted Magic card.