Most Prefered torrent client for mac

Hi All,
Which is the most preferred torrent client for Leopard ; the one which eats less amount of RAM and puts less load on CPU ? .
I Have been using bittorrent for OSX for last couple of days , but not able to get a impressive download speed ( which was pretty fine while working with PC).

I'm using wireless connection with Netgear WPN824 RangeMAx router . Should i do any special configuration for increasing download speed ?.

Thanks,
Nelson