Hi sweden, welcome to the forum.
Comodo AntiVirus has been improved during many months to catch up with AVG, avast! and the others. I honestly don't know how good it is today, but the virus signature database is being built up rapidly. Anyhow, we can expect a new version soon, which should have technology implemented from Comodo BOClean Antimalware, as well as malware signatures. So it'll only get better. I think that Comodo AntiVirus needs more computer resources (RAM usage) than AVG and avast!, but I'm not sure. The next version will be more efficient.
For more information, there are many topics around here which you can read. I'd recomment the
Feedback/Comments/Announcements/News about CAVS board.
/LA
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