I went there with a friend last night and found the burger to be very good. My friend prefers it to Corner Bistro. I don't, but it's well above average in a slightly different way. The Parker Meridien burgers are a bit smaller than those at Corner Bistro I think, and more roadside burger stand-ish. The bun's not that big and it's fairly soft, the grind is smaller than Corner Bistro, and we got them with everything, which seemed to suit them well. Decent fries too, of the medium-thin and crispy variety.
While on this subject, I want to report that I recently followed the advice of a couple sources (the Times a couple years back, and someone else) and ground my own beef for a burger. It's pretty damn easy: get some chuck, cut it into 1-inch squares, put it in the freezer for 1/2 hour, and pulse it in your food processor if you have one until it's the grind you want. Then toss it together into burger form, quickly and gently, and cook. It was the best burger I ever had, and I nearly swore I'd never have one any other way. (I know myself a bit too well to actually make a vow like this.) Still, I highly recommend that you try it.