Personally I would choose Avast and run it along with voodooshield free. No need for a specialized Anti-Ransom application. Voodooshield will cover more then any other. Then after you set up Avast in hardened mode with aggressive setting (I believe that's the option), you pretty much have all areas covered with a nice light configuration. 360 with avira and bitdefender engines on becomes quite a bit heavier then avast. Also the updates to the 2 engines seems like it is always a day behind.
My opinion.

Avast free with voodooshield free.