What Do I Look For In A Surgical Scope?

If one was going to buy a surgical scope (for a possible future career in electrology), what specifics should one look for in a scope? I found this one on eBay at an incredible price, but I wasn’t sure how well it would work for electrology.

http://cgi.ebay.com/TOPCON-OMS-75-SURGICAL-OPERATING-MICROSCOPE_W0QQitemZ170268599932

That one would work pretty good. I would say excellent, but after having worked with one similar for “mumble mumble” years, I can tell you that the best possible situation would be one where you can sit and look straight forward, and yet have the scope focused vertically downward.