The WSA is currently one antivirus that protects my Asus 1215N. Before it was Comodo Premium 6 which was excellent. ESET is not good, very heavy.
I have a 180 day free license for version 8.0.2.118 and I am very impressed how it protects my pc.
Never say a product is not good because it is "heavy" on your system; on mine it is very light even more than WSA. What may make it heavy is a possible other software that makes ESET to permanently monitor it.
Also dont say "Heavy" because it use lot of RAM; lightness on system responsiveness is not forcibly linked to RAM usage but to other factors.