One word... EPIC!
I put the 240 Mercury in my last Macbook Pro and it was fantastic, tests showed it always hitting 235 Mbp read and write.
I have the apple ssd in my current Macbook Pro, ( I need 500GB, btw OWC havent shipped a 480GB as yet) and I can at best get about 180 Mbp read and write, which is still great compared to a 7200 rpm HDD.
But having had the OWC one I know things can be faster than the stock Apple Toshiba Unit.
On another note, customer care from them was up their with Apple, I had to return another SDD and they reduced the restock fee from 15% to 5% which was very kind considering the drive was used.
The sandforce controller really does shine, you will not be disapointed, I only wish they had the 480's available to ship.
Btw I was booting in 17 secs on the OWC, and I boot now on the same system with Apple in about 22 secs, not that important I know but you feel that snappiness on the OWC in everything you do, good choice sir!