This strapless top is from the J.Crew Outlet. It's item #12646, and retails for $54.50 (the white was on sale for $39.99 when I tried these on). It is numerically sized, and was also available in a white color (at bottom of post). It is the same style as the Floral Eyelet top I reviewed a few months back.
The length is nice - on the longer side, hitting at mid-hip, and the top has side vents at the bottom to allow for a bit more movement.
I left these tops behind because I don't wear a lot of strapless tops. I preferred the blue top to the white (even though I think the white is more versatile), and couldn't be swayed by the price.