I have one - it is more than likely user error, but I haven't had any luck with it on three scopes I have tried - an MN190 (Mak-Newt), Meade 12 inch SCT and my C8. Each time I thought I had it right with OCAL, it ended up being badly off when doing a star test.
Others appear to have had better luck, so don't take my experience as necessarily correct
. Its a data point I guess.