At the risk of starting an all-out war, I've been looking into benefits of long vs short chain sugars, protein and fat in fueling drinks. Before I list what seems to be the common themes so far, let me state: whatever works for you is great - I'm only putting options out there and given the immense differences what works for someone may not for another, so options are a good thing to have. Also note that I'm referring sourced articles, but nothing beats reading those sources directly (if you have the time, and a critical mind) or better yet, a degree in nutrition (which I don't, but wish I had looking at this).
The general consensus on long vs short chain (i.e. maltodextrin vs glucose / dextrose / sucrose) is that long chain (maltodextrin) is superior in uptake to the "oses", but better again is combining long and short chain sugars for better absorption again. Articles:
http://firstendurance.com/2009/01/25/carbohydrates-for-endurance-review-of-current-research/
http://www.hammernutrition.com/hnt/1275/
http://www.livestrong.com/article/323040-the-maltodextrin-diet/
On protein, the consensus seems to be that a lot of studies comparing protein + carbs to carb only drinks often provide more calories in the protein + carbs drink, and that's why they've generally fared better when testing to fatigue. However, Hammer states that it is also provided to prevent catabolism (protein cannibalization from your muscles), which would seem to lend itself to better recovery. This seems to be a generally accepted effect from extensive cardio. Whether or not you need the protein before you finish or not doesn't seem clear, but shortly after is ideal to prevent muscle wastage. Articles:
http://www.joefrielsblog.com/2011/09/should-you-use-carbohydrate-protein-sports-drinks.html
http://www.hammernutrition.com/knowledge/how-much-protein-is-required-for-endurance-exercise.2892.html
http://running.competitor.com/2013/10/nutrition/what-runners-can-learn-from-bodybuilders_47941
On fat, there is very little it seems. There seems to be a requirement to maintain reasonable fat stores, but it seems this is not hard without excluding fat altogether. Ingesting fat while running (Perpetuem) is suggested (by Hammer) to allow your body to keep releasing fat stores and avoid going into starvation mode where it holds onto them. Articles:
http://www.ultrarunning.com/features/fats-in-the-endurance-world/
A common theme is that the better trained you are, the better all these systems work, so without solid training you can't expect great results (no surprises there). I believe that the mental aspect of endurance sport is also quite significant and if you believe your fuel is going to work better, it probably will (within reason) - I had a brilliant run the other day drinking a nice high energy electrolyte drink (SiS Go Electrolyte) because I enjoyed the taste. More importantly, if you can keep your head in the right place, you'll push through what you're likely to encounter with any fueling strategy - the point of "had enough and going home" (fortunately by then quitting and finishing often require you to get to the same point, so you may as well finish).
As a disclaimer, I tend to favour Hammer products at the moment, but like to mix it up when I can for something different. I think trying new strategies will always be an important part of my training as I expect no one has all the answers on this just yet, and I don't want to be doing things the hard way as these products continue to improve.
