We've deployed quite a few SSDs over the past 2-3 years.
Which one to buy depends on what you're after: speed, reliability or value. You buy an SSD for its reads; writing is a depreciating feature. I would never use an SSD for any non-static data storage; they should be limited to the OS/boot drive, where they excel at blistering reads. So you normally need to keep a separate HDD or array for data writes. If the machine is being used for any file rendering/processing (A/V file processing, etc.), you definitely need a separate HDD on board for that purpose, or you will quickly burn up the cycle count on the SSD cells. Right now, the sweet spot for capacity appears to be 128GB, which limits data storage anyway.
Knowing the chipset and the nand implementation are a good initial gauge of how an SSD should perform and hold up. But there are differences among the SSD makers in assembly and firmware competence.
The most reliable SSDs of the ones we have deployed are Intel, Plextor and Samsung, and in that order. Intels are usually priced at a premium, but quality costs, and they're the best. Intel and Samsung use in-house controllers and nand (except for some Intel models, which use Marvells). Last I checked, Plextor uses an excellent Marvell controller and Toshiba nand, is still assembled in Japan, is extremely trouble-free, and is very underrated. Not the fastest, but rock-solid dependable.
The fastest SSDs continue to be the SF-controller models, but depending on the manufacturer, are not always as durable/stable. Kingston, in its higher (non-consumer) grade products, also makes a solid, durable, reasonably fast product at a very good price. We've had a few SSDs using Indilinx controllers from other makers, and they are decent and quick. But I value reliability over speed, and lean towards the above three drives where it is a more critical application.
For now, try to find 30nm or larger NAND, which has a proven durability record and a better cycle rating than the latest 25nm. Although Intel's 25nm chips seem to be holding up fine, I don't have the same confidence with that provided to other makers. Most are now using 25nm chips, because it's cheaper.
The other big consideration with SSD is maintaining performance over time. Without GC or trim, the drive R/W speeds will eventually degrade. W7 supports trim, and should be enabled. AHCI should also be enabled in bios. There is a great freeware utility called SSDTweaker that will auto configure registry settings for optimal SSD usage. For non-trim OSes (XP, Mac, Linux), you should lean towards a controller with automatic GC (garbage collection). The better Kingstons and Plextors (Toshiba) have aggressive on-board GC, which in the long run, where needed, is a more desirable feature than having the fastest SF chipset. There are also benefits to modifying settings on many applications to reduce writes, such as disabling browser cache, and maintaining e-mail folders on another HDD. The more that writes can be reduced, the longer the SSD will last. Although, the design life expectancy of most SSDs is probably approaching the projected deployment life anyway. In another couple years, all of it may be a non-issue.
Migrating an existing machine to an SSD presents its own set of issues where a clone is attempted. Suffice it to say that I would avoid USB transfers and use the latest version of Acronis.
An SSD makes the most sense on a portable device, where its low average power draw, low heat emission, and shock resistance are most suited. But they will definitely speed up most desktops as well.
This is a developing industry with a fast product turnover, so the entire product landscape could be vastly different in another six months.
That's my 2c.
