I don't care about the resource usage. When I'm doing something big, like playing, I really cannot spare any resources on torrent downloading, or firewall or virus guard or anything. I'm not even online when I'm playing something my computer only barely handels. And there are lots of games my computer only barely handles. You see it's an overclocked piece of crap that tends to overheat a lot. So only time I tend to run Azureus is when I'm sleeping or surfing.
But I'm not a real number jerker. Azureus and Space Rangers can run on my poor old rig simultaneously and that's good enough for me.