I think Camelbak's are way under-rated in road cycling. Come on - we're not the pros and we dont' need to be super aero.
In the meanwhile, I see guys stuffing their jerseys with so much crap that it looks like a balloon back there.
I started using the Camelbak more regularly after extending my rides to 4+ hrs, and especially during fall/winter where a mountain climb could mean a 30 degree temp change from base to peak, possibly with unexpected rain up top. When you're going downhill at 25-30mph, wet and chilly, you start swearing that you'll never not bring a windproof heavier jacket to wear down in your camelbak.
I'm proficient at bottle grabbing (I can even grab them readily from a rear-mount bottle rack on my TT bike) but if you're using your camelbak correctly, it's definitely easier to drink on the move. Just put the nozzle in your mouth, and you can go - you can even hold it there and sprint/climb before you use it.
As for the hot back, yes, you will sweat more back there, but I'm usually sweating so much that a hot back is the least of my concerns. If you're worrying about sweating only on your back, you need to crank up the pace, as this isn't commuter cycling in street clothes we're talking here.
On long rides in variable conditions, Camelbak FTW. On short rides (<1.5hrs), ok, bottles might be easier to clean and fill, but the Camelbak is still easier to drink from.