I am curious to find out every one's feelings on training 2 muscle groups at once.

For instance, doing a set on you chest and then a set on your biceps and back and forth until you have completed the sets for each exercise?

Personally, I complete all my sets for that muscle before going to the next muscle. Reason I do this is because I find if I wait too long before I start my next set, the muscle has fatigue and I can't lift as much.

I've done this before and I plan on doing it again soon. From what I've heard, the best way to do this is with antagonistic muslce groups. So, you would pair up chest exercises with a back exercises, bicep exercises with tricep exercises, and quad exercises with hamstring exercises. I'm going to start supersetting all my upper body exercises for a couple of weeks because I'm going to start a plan where I do back, chest and arms on one day and there is no other way I am going to get out of the gym in a reasonable amount of time if I don't do it.