I run with a small camel pack and use TRAILWIND endurance fuel mixed in my water. It helps replace gels, chews, etc ... and replenishes your potassium and sodium as you lose it. (I am a heavy sweater and live in south Texas, so this is a HUGE issue). I can see where the sloshing issue can be a little annoying to some, but I have actually come to like it as it helps me get in to a rhythm and I find that I am able to focus more on my run. Might be a little of my OCD coming through. 

TEXAS, USA
current weight: 138.1

252
220.25
188.5
156.75
125