I used one both road and mountain biking. Won't ride without one. Mixed reviews - some people hate carrying the weight on their back... I use one 'cause I hate reaching down for bottles and frankly I will drink more using a Camelbak. Plus I also ride multiple bikes so the tools etc go in the Camelbak and I don't have to worry if I have something on the bike. It's a very personal choice - for me, it's the best thing ever! For others, not so much... pure roadies think they look stupid - frankly I don't care. I can add ice to the bladder and have lots of cool water on a ride! Clean out the bladder regularly and only use water, there should be no funky taste. Plus you get use to the weight... I have worn one (from smaller - Rogue, to very large - Hog) for years and hardly feel it at all.