the only reason i've still been playing quake wars over the past month or so is to fly the tormentor.

and of course, at first, it seems slow / weak / easy to shoot down, but that's mainly because you don't know what you're doing.

-The missiles take to long to reload? try changing to your other missiles while the one you just shot off is reloading. you have two types. the strong one that takes awhile to reload, and the smaller ones that take a very short time to reload.

-Getting shot down too much? It's probably because you are giving them a stationary target.
When I started flying, this infuriated me as well. It seemed there was no way to avoid getting shot down because the lock on warning comes up so late. But, if you keep moving, it's is much harder to get a lock on, and much easier to get away after a missile is fired at you.
What I mean is, don't hover and try to pivot around and shoot people, you have to dive in, shoot a couple missiles, and dive out.
Incredibly hard to do at first, but if you keep practicing you'll get there eventually.

Another thing that helps is using a controller. I hooked up my ps2 controller, and not only is it a lot more fun, but i fly loads better.
and if you don't have a controller, you need to up your sensitivity in the choppers to like 14.

So yeah, like anything, practice makes perfect.
At first flying is an incredibly frustrating experience, but once you more or less 'master' it, it's incredibly fun.


*edit*
and as far as it being an asset, unless the GDF really know what they're doing, often times i can pretty much single handedly stop the mcp from ever reaching the objective.