I would suggest you go with new tools to be safe. Used tools here in Doha are not good, it will break after some time if you will be using it heavily.

If you ask which brands are the best, Dewalt or Metabo are the best you can find.

Dewalt is available at TISSCO showroom then Metabo tools you can find at Gulf Incon showroom in Salwa Road.

Here are their websites.

http://www.gulfincon.com/
http://www.tissco-qatar.com/