SSDs get really complicated, but I will try to not melt your brain :P
Yes you want SATA3, even if your current computer can only run it at SATA2 speeds, its worth getting because all the SATA3 drives are 3rd generation and ALL have better parts inside and will run faster on SATA2 than a SATA2 drive.
Each SSD has 2 components that differentiate them, besides that its just a shell, none of these brands make the actual parts, they just put them together and warranty / sell them.
1) Controller: Like the CPU of the SSD
2) Flash chips: who makes them, size, speed, data type (onfi, toggle, ddr, asynchronous vs synchronous etc)
The major controllers are Sandforce, Intel, Samsung, Marvell, indilinx, and jmicron
Sandforce is the fastest, the drive you linked is a sandforce based drive. On all the SATA3.0 sandforce drives, there are 2 flash options, a entry level (asynchronous) and one that has 2x flash speed (synchronous). Sandforce gets their performance boost from data compression. They take your data, compress it in the controller, then send it to flash, the only problem is, a bunch of files you use are already compressed (game files, movies, MP3s etc), so when the sandforce drives hit a compressed file, they don't get that boosted speed. This is where the 2 different flash types come in, if the file is a compressed file, the better drives are almost double as fast, but a non-compressed file, they are very close in speed.
Im going to use newegg to link some drives just for reference:
Corsair 120gb force3 (you linked this drive): slow flash memory asynchronous
http://www.newegg.com/Product/Product.a ... 6820233206Corsair 120gb force3 GT: Fast flash memory synchronous
http://www.newegg.com/Product/Product.a ... 6820233191Those are just 2 examples, other brands do it too, while some ONLY sell 1 type of sandforce drives (either the best one, or the lower one)
-Kingston Hyper X SSD is only synchronous
-OCZ Agility 3 (asynchronous)
-OCZ Vertex 3 (synchronous)
etc
You can google the drive you are looking at (or ask me) to see what type of flash chips it has.
There are also other brands with different controllers:
The Crucial M4 SSD is the best selling non sandforce drive out there, this computer I am on at work (plus 2 coworkers, and 2 friends) has this drive. Its not quite as fast as the sandforce though, but is considered more reliable (this can be argued since they both had early firmware issues). And since it does not do drive compression, overall its not the fastest, but it tends to be very well rounded
Intel makes a few series of drives, the 3 series is a SATA2.0 budget drive, the 5 series is the Crucial M4 re-branded, and typically intel drives are more expensive and not worth it.
Indilinx was an early competitor to intel until sandforce came out, the OCZ bought them. Now they are coming back strong. There are some new drives (OCZ octane) that have very good real world numbers, much like the M4 it is VERY well rounded, in fact it tends to be a very promising tech, unfortunately its new, so I would wait for bugs. It also suffers from new memory that is 2x density, which means there are less actual chips, less chips mean less channels, means less speed, Ill bring this up next. All this means is if you want full speed, you have to shell out the cash for a 256gb drive!
Indilinx is also doing something weird and made a small SSD pci-e module, they call everest, and its supposed to be as fast as sandforce, but their ssd will have 2 of them in there, so will be even faster, here is an article if interested.
http://techreport.com/discussions.x/22296 It will be called vertex4, and will stomp my vertex3 in random files.
Ok, flash size is the final thing... Most of the drives you will see come in 64, 128, 256, (possible 512) sizes, and the sandforce will do 60, 120, 240, 480. Sandforce drives do have the full size of chips in them, but do "over-partitioning" for wear leveling, as chips wear out, it has spare area, it also uses this area as temp cache for its compression scheme. All with some sizes in-between sometimes (I had a 96gb, there are also 160s, 90s, but these are rare, and normally are the same as the next size up, but missing a chip or 2.
Where this actually matters is check the drive you are looking at mainly the write speed. Each flash chip has a wire from it to the controller, so if you have a drive with 4 chips, vs one with 8, the one with 8 is going to be 2x the write speed, since it has the ability to tap 8 lanes of flash. This is why the 60/64gb drives you will see have poor write times, there just isnt enough chips inside (and the octane drive with 128gb suffers from this too).
In conclusion, I would go for a Sandforce SATA3 synchronous drive (Corsair force gt, kingston hyperx, OCZ vertex 3, and some other brands), or a M4.
I have a 128 M4 in my work laptop, and a 120 Vertex3 in my home computer, roommate has the 120gb kingston hyper X, and Claire has a 96gb Kingston.