Very expensive in its day. If you can pick one of these up cheaply on eBay it's a good investment if you want raid in a PC or older server. Its limited to sata 2 so not much use for modern ssd drives. I have a stack of 2tb sata drives connected to it and both read/write performance are excellent. I tried a raid 5 on Intel on-board controllers and although read was okay write performance was terrible. Now on the adaptec the more drives I add the greater the performance benefit, as is intended by a raid setup.
The only let down is the accelerated ssd boost (MaxCache) only works with a adaptec branded Intel ssd which you cannot buy anywhere. Newer adaptec cards support most mainstream ssds but earlier cards are very limited.
The price was right, but would it work? I wanted to build a RAID array from four 3TB hard drives. turns out it is working great, but only after I flashed its BIOS with the most recent version from 2012. I also had to buy a set of SAS cables. And that was it. My RAID array has been running flawlessly in my old PC for about two weeks now. Couldn’t be happier.