I use "burst!", it's a little funky when you start it up because most of the time it starts other seeds I've done in the past that I don't want to seed at the time, so I have to close them. I don't know if it's me or the software, but it's not annoying enough for me to do anything about it.

I admit I sometimes download two at a time, but it depends completely on the situation. Like when it's two shows with only a couple of seeders, like to increase my chances of getting one of them. LOL. That's really the only time for me, because if I'm just doing one, it down and uploads both, faster. Your upload bandwidth contributes to your DL bandwidth in most situations.