The following is based on my investigations for purchase of my own solid state drive (SSD). Props to Xbitlabs for providing the baseline Sandforce ranking chart, and numerous other sites for the reviews and teardowns.
I used to not advocate getting an SSD, but now that I've used one, it increases responsiveness of your system immensely, assuming you don't have other bottlenecks like CPU or RAM. (Any recent dual or quad core processor, and 4GB of RAM or more, I would not consider a bottleneck). Also, the price has now dropped to around $1/GB on sales, particularly for the Tier 3 and 4 drives. Due to last year's floods in Thailand, the price of even the smaller (~500GB these days) magnetic hard drives will stay elevated through 2012, so the price gap has narrowed from both directions, making SSDs even more attractive.
An SSD will generally not improve your performance in games. It will decrease level load times just a bit, but your money is better invested in new/additional GPUs than in anything else for gaming.
All drives I looked at are latest generation SATA III drives. An SSD is a worthwhile upgrade in a SATA II system as well. Performance gains are still seen in SATA I systems with and without AHCI (like my laptop), but you won't see anywhere near the full potential.
I focused on 120/128GB drives since I consider that the sweet spot for usable space (60 being constraining) and anything else being too expensive. SSDs have their greatest strength at random read performance, something magnetic hard drives struggle at. I see the best usage of an SSD being in the “OS + apps” scenario. Don't yews an SSD for mass media storage, unless you're super rich; it's just not cost effective. Using an SSD as your C drive and a magnetic hard drive as your D drive/external storage drive gives a great balance of performance and storage space without breaking the bank.
The SSD market is very confusing, though it can be reduced to a rather simple matrix of controller and NAND flash type. A lot of the throughput marketing numbers used are maximums, or taken at high queue depths, and not necessarily representative of real world performance.
I am not aware of any “bad” SSDs on this list; even the Tier IV ones are still going to be considerably faster than a magnetic hard drive. Of course you pay a premium for the higher ranked drives, but frankly unless you're doing heavy file operations, you don't need that much extra speed.
When it comes to brands, I would say ADATA, Zalman, Super Talent and Verbatim would be “second tier”; not that they're historically bad companies, but they're relatively new to the SSD market. The other brands I would put at basically equal in brand recognition; choosing between them would come down to price and questions of warranty and support quality. Warranty is standard at 3 years, though some like Intel and Plextor (possibly others, I didn't check them all) are 5 years.
Some general notes about the technologies:
As you see, Sandforce is by far the most popular controller. The Sandforces will outperform everybody else in sustained read/write due to the yews of compression. However, the Sandforces will lose some of their write performance advantage over time due to the way they recycle used NAND cells.
The Marvells do not yews compression, and will generally have better performance over the long term, due to better garbage collection, among other things. Due to the lack of compression, is they will probably wear out faster than a Sandforce based drive, but not by any amount worrisome to the average user. Other things being equal, 32nm NAND will last longer than 2Xnm, so you could pay more up front for that if you really wanted to. See also life expectancy below.
Samsung and the OCZ Indilinx proprietary controllers are relatively new to the scene and are good choices as well. Samsung and Indilinx seem to emphasize read performance to the detriment of write performance; for most users this shouldn't be a big issue.
Life expectancy varies considerably with usage, and depends both on the controller and the NAND flash; suffice it to say, for all but heavy media/server usage, the rest of your system will be obsolete before you have to worry about flash endurance issues. We're talking 10+ years for the average user. Intel calculated one of their drives, can't remember if it was the 510 or 520 series, at 18 year life with 10GB written a day, which is a lot more than most users will do. Smaller drives will wear out faster than larger drives because there are fewer flash cells to share the load.
Sandforce SF-2281 SSDs
Tier I
Synchronous 32nm Toggle NAND
OCZ Vertex 3 Max IOPS
Patriot Wildfire
Mushkin Enhanced Chronos Deluxe
Tier II
Synchronous 25nm ONFI 2.2 NAND
Intel 520
Tier III
Synchronous 25nm ONFI 2.2 NAND
ADATA S511
Corsair Force GT
Kingston Hyper X
OCZ Vertex 3
Patriot Pyro SE
Zalman F1
Mushkin Enhanced Chronos
Synchronous 24nm Toggle NAND
Sandisk Extreme
Asynchronous 25nm NAND
OWC Mercury Extreme Pro
Tier IV
Asynchronous 25nm NAND
ADATA S510
Corsair Force 3
OCZ Agility 3
OCZ Solid 3
Patriot Pyro
Kingston V+200
Super Talent Tera/Drive Nova
(Verbatim 47378)
Marvell 88SS9174 SSDs
Tier I
Synchronous 32nm Toggle NAND
Corsair Performance Pro
Plextor M3
Synchronous 24nm Toggle NAND
Plextor M3 Pro
Tier II
Synchronous 25nm ONFI 2.2 NAND
Crucial m4
Other SSDs
Samsung proprietary
Synchronous 24nm Toggle NAND
Samsung 830
OCZ Indilinx Everest
Synchronous 25nm ONFI 2.2 NAND
OCZ Octane