What partition map works best with Mac OS x 10.6.8?

I have a 2 TG WD external hard drive. I plugged it in and no notifications popped up asking to format it so I set it up with Time Machine to back up my hard drive as well as a 1 TG hard drive (which I'm currently having issues with. See here https://discussions.apple.com/thread/5283697). I then read online (here: http://www.456bereastreet.com/archive/200901/reformat_and_repartition_hard_drive s_before_using_them_with_time_machine/) that the Master Boot Record partition map is not good for Time Machine. This new 2 TG is set up as a MBR. My 1 TG is a GUID partition map. They are both formatted as Mac OS Extended (Journaled). Do I need to change the partition map on the 2 TG external hard drive? (This website (http://macs.about.com/od/usingyourmac/qt/partition-types.htm) seems to say the MBR is only for Windows, but then why did the 2 TG allow me to set it up with the Mac if it was set at MBR??)