I did not buy from Amazon. You can get new one from eBay much cheaper. Just be aware of sellers' rating.
Sad news from HDD from SSD is that you will have to sacrifice big gigabytes for SSD unless you can afford 512GB.
However with external drives so cheap lately, no need to hog all 500gb. I found 128GB enough for me to do productive work, including Parallels Desktop.
Whole installation took less than 20 minutes. Just unscrew your back of laptop and pop old one out and put new one in. If you use MBP, securely fasten with two black bars so that it does not touch the surface of your MBP. Or simply, check out some youtube videos.
I find dramatic speed improvement. What took me 40-50 seconds to boot, now takes 18-20 seconds with all heavy programs (Adobe suites, Parallels, Office 2011 mac and more). I think it took like 15-16 seconds at factory setting. So you won't regret it.
Open iTunes, or calendar. Icons on the dock bounces only once. Heavy one like Photoshop bounces twice at most.
I can now agree with people who purchased earlier saying that they can never go back to HDD.
It really feels like a new laptop with $160 SSD(128GB) upgrade.
Yes, I recommend it.