I received an 850 MB HD XT (8-bit IDE, 40 PIN) for my Amiga 500 but I own a GVP A500-HD+ which only support 50 PIN (SCSI) HD.
If you have some money to spend, then don't bother (unless you need what's on the drive) and try to find a decently sized SCSI drive that isn't too old (or hasn't seen much use).
While 850 MB can be a useful amount of storage space, it's quite old, and if it has been used a lot then it will have been subject to a lot of wear and tear. Getting a new drive is always the best solution (more reliable).
