Which One: I'm using 2.0.1 (build 19248) on a PC that is running Win XP x64 SP2. What I Like About It: In a nutshell, everything. It performs the basic function I need for my BT client to do - the only function I need it to do - which is to upload and download...which it does without wasting system resources on other functionality that I neither want nor need in my BT client. It runs 24/7/365 with a relatively small footprint, doesn't crash (at times I've gone as long as four months without rebooting this machine), and - at least with the router and ISP currently in use here - doesn't make me jump through endless hoops to get ports to stay open so I can seed. The newer versions haven't improved anything I care about and haven't added anything that is even remotely useful to me, so I have not and will not bother switching to them.