There is a complete security suite available from ESET as well if you want the extra real time scanning capabilities. The biggest problem with Avast is performance. ESET majorly outperforms Avast in just about every area when it comes to resource usage.
It really comes down to preference. Of course Avast is an extremely powerful suite and works for most people, but I always prefer resources efficiency over features any day.
No sense in spending the money if you feel you are adequately protected with Avast :) That is why it is the one I recommend first, for a corporate environment ESET typically offers equivalent protection with minimal resource usage across multiple systems. :)