The research is pretty clear. A generalized summary would be to consume 20 g protein, 30 to 40 g carbohydrate, and some form of electrolyte replenishment. I do not make specific recommendations. But I do recommend that weight loss clients make every effort to schedule/time their meals to be post workout nutrition. If other clients are looking for weight gain, eating before and after is my recommendation (but not to eat heavy meals right before working out). And for those with little time to prepare meals postworkout, I recommend preparing in advance (which can save time for more than just exercise). Preparing well planned meals to place in the fridge to eat later will help anyone to eat better and save time.
I agree that combining both carb and protein post-workout are helpful and important. A lot depends on the type of workout. Carbs are especially important if the workout is a maximal effort cardiovascular workout to ensure adequate glycogen replenishment. Protein if the workout is a maximal effort resistance training workout.
It all depends on the client, his/her training regimen and any medical conditions that might be present (such as diabetes, kidney or pancreatic diseases, etc.). Personally, I would go for both protein and carbs. I don’t put much of weight at what drug using bodybuilders say, especially those who are sponsored by supplement companies. Again, a well-balanced diet plan is enough to provide all of those nutrients your body needs to recover and repaired its self from any type of workout.