Hardened mode is good but gives false positives like exe files from Tune Up Utilities, Installers got blocked for me.
Hardened mode blocks almost every single unknown file. I have 13 here on my desktop. Already submitted.
Emsisoft is great i can tell, they have a high ram Usage (about 100-150 mb in a VM for me. But not really that much slowdown.
Also they have a great firewall and behavior blocker.
F-Secure is also good, but it blocks some legit applications.