Running Avast 5 and MSE together

I found this interesting site regarding running both side by side. Any opinions?

http://www.freepcsecurity.co.uk/2010/03/09/tf2/

Its interesting yes but i should never use 2 AV on my system …

Vlk does not recommended to run avast side-by-side with MSE.
ThreatFire can run with avast. Just that I don’t have patience for it (if I set to answer questions) or it does not detect anything (besides avast).