I had a 120GB one of these fail at about 6 years old, which ended up silently corrupting the data.
(Not even S.M.A.R.T. admitted that there was anything wrong with it. )
I don't know how common this is, but I've included them in my product recalls anyway; if you have some, then I strongly recommend replacing them with a good model, as soon as possible (hopefully before it's too late). When you don't need them, they should be destroyed to prevent anyone from re-using them and losing their data.
This leaves me very wary of any SSDs with SandForce controllers in them. (Not that those don't have a bad reputation already.)