I don't know if I can convince you,but I already convinced a lot of other people...
Been an Avast user since Avast32 free,and now I'm halfway of my 3-year Avast Pro subscription.....The program had it's better and worse moments,but problems or bugs were fixed quite fast,unlike some other virusscanners.
A while ago,I had to fix a friend's computer,which started behaving very weird and unstable.....his Norton Antivirus 2004 updated automaticly to the newest definitions,so he was totally convinced that having a virus on his system was impossible..
I uninstalled his Norton,cleaned all it's traces and installed Avast Home...
SURPRISE.....!!!
Avast detected 3 different virii that already infected
11 files/folders.....deleted them,rebooted,and his computer ran like a breeze again...
He is convinced now......