TweetWell, it depends on the superset. Does he superset antagonist muscle groups or the same muscle group?
I like both but the same muscle group is more of a high intensity approach and requires more rest, IMO. For example, you have the chest/back, bi/tri, ham/quad approach which is the antagonist approach. These muscle function completely opposite of one another.
Then, there is the same msuch approach, which I also like very much but it really taxes the muscle alot more. For examlple, I will do bench press (db or bb) with db flies, incline press with incline flies, leg extensions with squats, pull ups with scoop rows, dead lifts with seated rows, bb curls with hammer curls (this one actually changes from more bicep to more brachialis-sp?), dips with push downs and so on.
Then, I have my 'that don't make any sense' superset. At least, that's what I hear when I do them. On this, I superset stuff like chest/calves, quads/biceps, delts/hams, etc. With this approach I'm basically just trying to use exercises that don't take away from one another but are more stimulating on the CNS than just antagonist supersets. Supersetting bb curls with tricep pushdowns just doesn't compare to the stimulus of supersetting bb curls with squats. So, I like to mix it up.
The best thing about supersets is you get out faster. In stead of sitting around between sets you are doing other exercises. So, you get done faster, you keep your HR higher and you really work the CNS pretty good. I dont' recommend you do them all the time unless you really mix it up. But, that's my opinion.