Lahat nmn ng commercial anti-virus has that auto-update feature.
AVG consumes a lot of memory alloc that why you encounter slowness. Di ko gus2 ung UI nya, not very intuitive neither easy to use. Good feature is that it scans site right on your browser and tells you if the site is clean or not. It adds to the lag time as well, that's the drawback. NOD32 is a better choice of the two.
But for personal use, I'd rather stick to simpler Avira personal. 0 intrusion pa nmn ako so far and detects worms, spywares as well.
Bottomline, it all boils down to your personal reasons. You can try them all if you like and just select what's best for you.
