I have a CB MULE (100 oz) that I mostly use for hiking, but I've found it handy on long rides out to the boonies and also commuting to work. I do find that it gets a little warmer, but for me it doesn't outweigh the benefits. I like not having to reach for the bottle (I have to stop pedalling to reach and drink, I'm not that coordinated yet). I also like that I can bring things that won't all fit in my saddle pack. I'd like to get a light weight jacket, I know that will fit (my hiking jacket fits and its bigger/thicker than the cycling jacket I have my eye on). For commuting (20 mi each way) I don't even put water in it, I just use it for my wallet, hair brush, keys, etc. I'm not big on the idea of riding with a huge back pack with all of my clothes and lunch in it, so I take those with me the day before I ride and then just bring the little stuff in the CB. So handy!