I would feel weird about giving myself a rare and ultra-high-prestige name. But, I have no idea how the Chinese would perceive it.
I've read that a number of Chinese with the surname 欧阳 [Ouyang] logically chose the English surname O'Young, confusing a lot of people who were led by the name to expect someone more Irish.
My teachers at DLI were really into historical dramas. I'm more into shows with lasers and robots.
Er... 司馬 isn't that rare, and people would rather advise you to select a rare but prestigious family name, rather than a rare and unknown one.
It's like given names in English: if you pick a rare and unknown name (or even a common one with an unusual spelling), people are just going to go "huh?"
马丁 not only captures the english sounds somewhat reasonably, but it also surprisingly captures the meaning in an interesting way: martin is based on mars, the god of war, and is also a famous figure in christian history as a roman soldier on a horse.
the chinese characters are: 马(ma): horse, and 丁(ding):soldier
you can hardly get any closer with a resemblance of the meaning in both languages.
My Chinese name is 司馬文 "Sima Wen", with the surname being that of several series of famous Chinese historians, emperors, and generals, and my given name meaning culture.
My teachers were very proud of that one because it closely resembles my English name and they said it sounded dignified. I can only assume they knew what they were talking about.