I demoed a 2009 BLX Pro Open after hearing your (PP) rave reviews on the racquet. I could not get in a groove with the racquet. Yes, it was softer and less powerful than a Pure Drive but I didn't experience the more feel that everyone talks about. Part of the problem may have been that I demoed it next to a 2012 Pure Drive Roddick which easily blew it out of the park. The PDR did everything a little better for me than the Pro Open. It didn't have any of the hollowness that the Pro Open had.
Take my review with a grain of salt, though. I am probably not the intended user base for the Pro Open as my racquets of choice for the past few years have been Dunlop 200s and Pure Storm Tours.