Teamviewer Alternatives?

Besides UltraVNC (which I heard is already a really good choice):

-AmmyAdmin
-LogMeIn
-RealVNC
-splashtop

But you should be good to go with UltraVNC in my opinion.
Hope you are able to find a good solution.

Try using GoSupportNow remote support tool.; It is easy to use and costs only $19.95 / month, next to free.