Yes. Totally. Except for G-6, that thing blows.
Wait, what? Are we talking about the same G-6?
It has 3 fast firing 30mm cannons which completely annihilate everything in mere seconds. Afaik only the Me262 has a higher one-second-burst mass. It's one of the best high tier planes in the game I'd say.
It doesn't until 720k XP on the plane. Good luck grinding there with the single (actually slower firing) cannon and its 65 rounds, while the plane handles as if the gunpods were already installed. Thanks, but no thanks. By the time I got to not even 150k XP with it, I already had the G-10, which is a vast improvement even though you start with "only" the 20 mm cannon (but playing that plane doesn't feel like such a grind since the 20 mm is enough and you can unlock the 30 mm later if you want).
I guess to an extent you could compare the G-6 to the Mustang (even though I actually shot down quite a few G-6s with my P-51), you get used to it and you can make it somewhat work, but there are planes that give you much more reward that it is simply kind of pointless flying it (sure, you can say it's not about winning/rewards and that it's about flying your favorite plane.. but since the 109s look basically all the same...)
