I just have made a fresh install of Mavericks on a brand new Samsung 840 EVO SSD of 750 GB and thus swapped the old Toshiba HDD which came with my mid-2012 15 inch MacBook Pro. It is absolutely stunning. Reads and writes reach 500 MB/s, just as expected. The only downside I noticed is that it boots up in around 30 seconds, which is kind of lame.