Why does it matter about the terrain? I don't bother for any ride less than that anyway, and only bother with it on longer rides partly as a way to make myself drink, if I just take water I don't bother, the thought of wasting High 5 provides encouragement!
Have found Nuun tabs to be really good and they allow you to manage the carb loading separately. Tri berry tastes nice and has a slightly effervescent feel to it.
A small tube of Nuun tabs will handle even the biggest of weekends away and dead easy to use for topping up from burns en route. Would never go back to anything powdered.
I use Torq and High5. I'm preferring Torq as of late because:
1. They're cyclists, sponsor and turn up at cycling events
2. Their stuff seems to be really soluble and doesn't upset my stomach
3. They sell refill bags so you can refill their tubs instead of binning them.
I won't touch SiS or Lucozade because they use artificial sweeteners (Acesulfame K and Aspartame). I mean, why? It's a bloody energy drink, FFS. It's supposed to be full of carbs!
Second for Allsports International stuff – Winter or Summer Training Formula (or SR3 if you're just after an Isotonic) – and a big fan of Amino Load for recovery drink – http://www.allsports-int.co.uk
