Most of my training "career" has been spent doing upper/lower splits. They allow excellent recovery and allow intensity to be high all the time on most training sessions (important for pushing it 100%). Good for joints too.
Have drifted away from them (upper/lower) occasionally, only to return again some time later when feeling fatigued.
Sometimes I split it up so that I do arms after upper body (sounds strange...considering you indirectly trained arms the day before, but it works, and still allows good recovery/progress).
That ^ is controversial on here (we are bodybuilders, not powerlifters), but it works really well for me (especially considering when I push it 4+ days per week with compounds etc I reach a point of diminishing returns).