So to continue the discussion that was derailing that PvP thread....
The Master in the new series was only featured twice. Both with 10. I think they presented an interesting story, but his "mastermindedness" was pretty average. If you look at all the other episodes in the newer series the seriousness of the plot was no different than any other alien that invaded Earth. Both of his introductions into the episodes were strong, but I feel like they fell a little flat. I'm not familiar with the 'Old School' master so I can't compare.
I'm really digging the new series. I started with 9 and was mad when Tennant took over (I hate U.S. movies and TV shows that replace main characters in the sequels, but still have the same name). That didn't last long. 11 didn't take over as my new fav because he's still too "friend-zone ish" compared to how dynamic 10 was.
I recently started going over the original series - at least with what's on Netflix - and have gotten as far as 3. It makes me laugh at all the mock-super nerds that are raging about Peter Capaldi being chosen because he "can't cross his own time stream." They did it in the originals. More than once.