I would always recommend a new one. You can never know how worn the gears are in a second hand one before you buy.
Ps. Please don't post any more ebay links. I won't delete them now, cos you are illustrating a point (I won't complain if you edit the post and remove them yourself though), and you are new, but normally they are not allowed, except under exceptional circumstances (a good example of which would be as above, where I asked you what car, and you showed me the auction. That's OK, but those servo links are not, as they are not necessary in order to ask the question). Just FYI. No problem.
