Hi ReneK,
My own experience with KAV6 is very different from yours. I have not used Avast Pro so will not attempt to compare, although there is not quarrel as to the detection rates.
I have used KAV6 since before it came out of Beta. It runs well on my system without conflicts, uses fewer resources than any other AV I have tried, scans in less time - 2 minutes to 16 minutes for a complete system scan, and in general I like it better than anything I have used including Bit Defender, NOD32, Avast Home, and AVG.
I am not wedded to any software, but use what suits my purpose and system better.
If anyone is looking for an AV, they should trial KAV6, NOD32, and a few others including Avast. But your experience is not normal, and your assessment is inaccurate as a general statement.
Regards,
Jerry