My experience was similar to yours, Carl. The only computer I've seen with McAfee had a performance problem that I solved by taking it off. It's hard to say bad things about McAfee though as the company is local to my area.

I'm using Vcom's System Suite (it uses Trend Micro's anti-virus engine) which seems to work well enough for me. I got started on the predecessor back when Norton's programs got bloated.

I expect that the reason some of these suites are performance hogs is that too many of the features are turned on and running in the background.