I did research Cornerstone, and was very impressed with all aspects of the company - tech support responded promptly and informatively via e-mail, sales was available, all toll free calls, 5 year warranty (with $35 advance replacement optional), and this guy Jim (hardware guy at Cornerstone) seems to be very helpful in the Toms Hardware forums.
Also, THEY MAKE THE MONITOR. How many times have you been able to get such great access to and help from the manufacturer of ANYTHING you bought!?
Of course, I now have to take a look at the monitor itself. I ordered a P2450 - very nice specs and only $13 more than the Samsung 955DF. I'll let you know...