I don't know the full service of the VIII but I know it saw dedicated service over the jungles of Burma. It could certainly beat a Zero into submission, even at its own game. There were only around 1,300 VIIIs built, if I remember correctly. This shouldn't give the idea of an inferior plane. Remember the VIII was a new airframe while the IX was just the old V airframe with a Merlin 61 engine.
There's no denying the IX was a good plane, but the VIII, in a lot of peoples opinions, was the greatest Merlin engined Spitfire.