Pros are that it works and is cheap. Only paid $6.99 each. No fitment issues with OCZ SSD and Coolermaster case's 3.5" slide-in drive trays. Supports two 2.5" drives which is great, though for heat producing magnetic drives you may want opt to put them in separate adapters. It would work perfectly fine for SSDs that produce little heat.
On the negative side, the horizontal bar of the adapter gets in the way of using a 90 degree SATA connector, so you will have to use a cable with a straight SATA connector on the end going into your drive. I prefer a 90 degree end on my hard drives SATA cables due to how my case is arranged. Note that you would not be able to use a 90 degree end on the top drive if you put two drives in the adapter.
I purchased two and they both had mediocre or poor paint jobs. The black paint had obviously run before it dried pretty bad on one, though the second one was slightly better. Not that it affects performance or fit sine the paint is very thin, nor will really very be visible once installed--it was just disappointing from Thermaltake. The boxes they came in had better finish on them.
This is a stamped and bend piece and the material is very thin. While you will probably be ok, I would be somewhat concerned about stripping the screw holes. I am using tool-less drive trays, however.
I also own a Silverstone adapter which I like a bit better as the mounts are offset to allow the 90 degree SATA connector and the more simple silver finish is of better quality looks nicer in the end. It is also a considerably heavier gauge material so I would assume there is less risk of stripping the screw holes. While this Thermaltake piece works just fine, I'd probably opt for the Silverstone again (currently only $1 more at $7.99) if purchasing another one.