Heh, a crack squadron of Ares can disable and disarm anything smaller than a destroyer in a flash. A gigantic secondary capacity coupled with a reactor big enough to keep up with Maxims means long-ranged beatdown.
Expensive? Definitely, but I'd bet the Hercules was expensive when they first shoved it out into the field. When you're up against the wall, it really doesn't matter.
In any case, the Ares may be useless in multiplayer dogfighting, but in the FS2 main campaign, it definitely kicks butt and takes names.
However, the Mara... can you say better than the Shivan version?
Speaking of the Erinyes. Is it just me, or was it not that great even when you first see it? I mean, one of the squadrons "saving" me was completely annihilated. The shielding isn't great, the armour only a bit above average, mediocre speed and agility, and small secondary payload. It's only saving grace is the quad primary banks, but the crappy reactor they stuck in means it's useless once you put anything bigger than a Prometheus S in it. The paintjob's nice and all but did the thing have to look like a bunch of bananas?
I flew the Erinyes the first time I played the campaign, but I wasn't impressed.