OK my two pennorth.
First off, I have the Justflight version of the Aeroplane Heaven Spitfires; as Nigel said, they are not bad, pretty good actually - their big plus point is, of course, the comprehensive nature of the packs covering most variants (of which more later) from the prototype to the Mark 24. I also have the freebie Aeroplane Heaven Seafires, which are equally good.
The Realair Spitfire 'only' covers one version, the mark XIV, but boy does it cover it!! Absolutely superb, when it first came out it was bleeding edge technology and it is still one of the finest aircraft I have ever flown in FS9; and you do have to fly it properly, the realism modelled into the FDE ensures that, had to do more than one dead stick landing in the early days with oily smoke pouring from under the cowling.
The Plane Design Spit again covers one version, the mark XVI lowback. Wing_Z, I find it ok to fly (about comparable to the JF/AH Spits), you might want to check which version you have; mine is version 1.1
That leaves some gaps in the lineups which have now largely been filled by freeware designers. Actually a couple of those, the mark VII and mark XII, are models that predate all of the above; they were made by Paul Rebuffat (originally for CFS2 I think) and they are still visually pretty good - lucky really, as nobody else has ever attempted that first Griffon Spitfire. There is also a freeware Spitfire from Mr Lucariny; it is ok, I guess, but doesn't exciter either visually or dynamically.
Which leaves, of course, A.F. Scrub who is now producing some very nice models; some of his earlier versions were a little suspect in shape (although massively better than anything I could do), but he (?) has refined them over time. The one remaining gap, the mark 21, has been covered by this fine modeller, and a fair view other marks as well; in addition he has covered pretty much all the later Seafire variants, as well as the Spiteful & Seafang - oh, and a quite decent Hispano Ha 1112 Buchon, the Merlin engined bf 109, if anybody fancies recreating the film Battle of Britain.
I don't have the A2A Spitfire, so can't comment; didn't see the need, as I had covered every option already.
So if you want variety, go the JF/AH route; if you want seious realism & stunning models, go the Realair route.
