109f for base defence, and it can hang with many late war monsters for a while.
109g2 is my fav. guns just seem more lethal even though they are the same... maybe the plane just handles better.
i never load the gondolas, except a g10 with the 20/30mm double package to kill NOE lancs. thats about all i'll fly it for. intercepting a NOE buff mission.
you can get a 109e off the runway at a vulched base easier than a zeke IMHO, and you will turn almost as good. the guns only bruise tomato's so be prepared for some serious spraying a wing to get a kill.
g6 is just not my friend. whenever i fly it i get bounced by a high la7 or spit IX and die. i could take off 3 sectors back and still find a spit or something higher than me it seems lol.
like some said, if you can get used to the tater, you will kill many many planes, though there seems to be some discrepency on the hit power of it lately. i personally have such bad aim in general i can't use it (except in the above mentioned load with the gondolas to kill buffs up close and personal).
there are some other JB's (11, 22, and others) that fly the 109 more than myself, and can kill me 1-1 every time, look them up and they's probably help.