I purchased a 2011 MBP 15" w/ 8GB and 500 GB 7200 rpm HDD, 10.6.7. Both SATA ports show 6Gbps. I purchased an OWC DataDoubler and an Intel 320 series 300 GB SSD - after searching and reading as thoroughly as possible about the various issues. It seemed to me that the Intel 320 would be stable and likely trouble-free even though it only negotiated to 3Gbps (as expected). I installed the SSD in the DataDoubler because 1) the drive is supported only on one side with two screws by the DataDoubler so it seemed to me that for a spinning / vibrating drive it would be better to leave the 750 GB drive in its original location where there is support on both sides of the drive; and 2) others have indicated that the original location has SMS support which is not present in the DataDoubler / optical bay location. I used the Trim enabler as others had suggested that would be helpful with the Intel 320 series. At any rate the installation was straightforward and the result was amazing. I placed the system, applications and some development tomcat servers on the SSD and put the home directory on original HDD. Boot times were seconds and the launching of apps the amount of processing that could be sustained with seeming ease was amazing: 3 tomcat containers with eXist XML DBs, 3 eclipse workspace instances, 1 VMWare Fusion instance, Photoshop, Aperture and miscellaneous other apps all running effectively at the same time. I used the machine for field recording and audio processing for a two week period and all was flawless. The upshot is that I finished the production of two DVD masters of mp3s and audiobooks on a Sunday evening and put the MBP to sleep via my usual method of selecting Apple > Sleep and the next morning the system was dead - the SSD had reverted to 8 MB capacity. I had left the original system install in place on the 500 GB HDD so I was up and running pretty much instantly but still had a whole mess of system re-organization to deal with since none of the apps that I use were installed on the HDD. The Intel 320 SSD probably could have been resurrected but the tools to do this involve dealing with DOS apps on a CD and so forth. There's no Mac friendly way to work with these drives at this level - I can't speak to the other SSDs on the market but it is my impression that this area of working with SSDs is really a kind of hobbyist activity. It takes more effort than I can warrant for a production machine that I rely on for day-to-day operations. My configuration was wonderful for the 30 days that it worked but I need a system that I can have a better expectation of continued functioning. I've gone back to a single Samsung 1 TB drive and wish I could once again experience the snap and capacity of the SSD + HDD configuration but it takes me typically a day to recover from a failed HDD and things are more complex and retaining a SSD backup seems unpredictable since I have no idea why a 5 year warranty drive failed in 30 days. From reading various forums it seems to me that there is some sort of marginal interaction between the MBP + Mac OS and the SSD. In particular there are some claims that when sleep is engaged the MBP may apparently drop power on the optical drive bay rather precipitously and this may interfere with the SSD shutting down. I have no idea if this is possible but it does make some sense to me that the optical bay was likely not designed to the same requirements as the usual HDD/SSD bay. My conclusion is that the MBP is not actually designed to support the particular configuration of two drives as I used it. Maybe I was too cautious in not putting the HDD in the DataDoubler - I don't know. Lest anyone think I was totally luny going into a field recording with an experimental configuration, I actually had a backup "normal" MBP and secondary recorders in operation. Anyway that's my tale. May it save someone else some stress.