Performance of Kaspersky in 4.0

What is everyone's experience of the above? Kaspersky has been a real pain when I use 3.0 by slowing my VM to almost a grinding halt. So wondering if it is worthwhile installing it in 4.0 given that I have paid for it.

Does anyone manage to train Kaspersky to classify SPAM correctly? This is another beef I have for it seems that Kaspersky keeps labelling my one of my incoming emails as spam.