Depends what you want to do, what your expectations are etc etc. A PVM monitor has no input lag at all, an OSSC has no input lag, but most displays it connects to will have some. A PVM is compatible with light guns, an OSSC set up isn’t. A PVM handles 240p to 480i transitions perfectly, an OSSC setup loses the picture for at least a split second. On the other hand good luck getting a PVM in the sorts of sizes you can get HDTVs in these days and good luck playing 1080p or 4k content on a PVM.