My take on it is that the 109G10 is probably one of the best 1v1 planes we have in the game. It has an advantage over every other plane we have- the advantage might be different for each plane, but it does have an 'edge' over them. It is just a matter of flying the G10 to its strengths and not to your opponents. Now, in a typical MA environment it isn't so good. It lacks the firepower for a 'quick kill' (unless you get VERY good with the 30mm, and with that it lacks endurance, the gondolas just hurt performance to much to be worth it), turning and manueverability is good but not great, and you can't really get super fast for perpetual bore n zooming (because of poor high speed handling).
The Dora is a superb plane for the MA, but it is less good than the G10 for a 1v1 fight. The Dora packs enough firepower for a 'quick kill' (think 1 pass, cherry-pick, whatever), it has good high speed handling so you can stay a lot faster than the people you are bore n zooming, and it is fast enough to run away from most planes. On the down side, manueverability is just atrocious compared to the G10 (at anything less than high speed, where the G10 will be starting to 'lock up').
A well flown Dora can surprise a lot of planes in a 1v1, but a well flown G10 is just about untouchable by anything other than a Spit 9.