Kaspersky is another reason I love my job. There have been times where a computer comes in and its "not working".
In reality, Kaspersky has brought the machine down to a grinding halt. All i have to do is boot into a live environment and delete all traces of it.
It seems AV protection is a see-saw of performance and security. many time too much security is just redundant.
With that being said Kaspersky is probably the best AV out there, but that is like saying one it's the best bolt for your front door when the criminals are using the side door or garage.