I do my more intense cardio on off days, but sometimes do a 'cooldown' sort of cardio for 15 minutes after weights.
Studies show it takes a lot of pressure off the heart to do the cooldown cardio.
I do all my cardio for heart/health benefits, not fat loss. Not eating too much keeps the fat off, and GH
doesn't hurt either.
I like being able to walk around without being out of breath too.