Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
I also use the JustFlight Spitfire- although unfortunately I do have a couple of issues with it that detract from my enjoyment.
The first is that it doesn't work as AI - it takes off, calls crosswind, but just keeps climbing straight ahead ad infinatum. But it was never meant as an AI aircraft, so it's allowed to not like being one!
The second, more serious, is that the simulation of the loss of power when rolling inverted is apparently achieved by just closing the throttle and holding it there - the engine never actually stalls out, which is what the carburetted Merlin did if you put it upside down, because there was no fuel reaching the cylinders. The ability to flick it upside down, hold it there, flick upright again and keep flying without the engine missing a beat does take away from the simulation of the type somewhat.
It's a good package, with a good range of models and paints, but it wouldn't get onto my "must have" list I'm afraid.
Ian P.