Using SSD for video, is there any performance gain over HDD?

The specific task is not the important issue.  Whether you read / write video files, or CAD drawings, or anything (large or small) doesn't matter.  The concern with SSD drives, other than firmware, is known as write endurance (or write exhaustion, by some).  In other words, even though they have no moving parts, the memory components (NAND) will eventually lose their ability to hold power (and therefore not record) based on the number of P/E cycles (program / erase) the drive experiences -- regardless of what type of file is written (and / or erased).

Size of the drive will impact this, since each NAND on a larger drive will experience few P/E cycles.  The type of NAND is also important.  Studies have shown (and are readily available) that, with an 80 GB SSD drive using 3X MLC NAND will typically withstand 5000 P/E cycles.  That translates to about 114 TB of data written / erased from the drive.  

Assuming you write 10 GB per day to the drive, that would be 31 years before failure.

That's a bit of an oversimplification -- but it should help you understand the issues with SSD drive.  Brand matters, as does the firmware.  Power failures can also have an impact on SSD -- so be sure they are on a UPS if you want them to last.

Hopefully that helps you make a decision.

Mr.C

hmm I'll have to figure out the math to see who long an scandisk Extreme 240 GB ssd is going to last then

Is it an Extreme, Extreme II, or Extreme III.  Each uses different NAND's.

It is the base extreme SSD which is the 24 nand. The extreme II uses 19 nand size. Regular extreme uses the sandforce controller while II uses marvell. From what I understand the sandforce 22xx line of controllers are very slow when writing non-compressible data (liek video and etc). Not sure if they fixed that problem as I can't find any additional info on it. Thanks for the math formula.