I love this bag. It carries the essentials for day hikes, rides, + trail runs. It sits high on your back so the 3L of water is barely noticeable, other than the slight bulge when full because there is no plastic structure.

It vents relatively well (small footprint) + is pretty sturdy w/o using the waist belt (more like stomach) or chest clips, which i rarely use unless running.

It is big enough for a day of essentials shell, lunch, water, gloves, + that is before you start clipping things on to it.

Described as a mountain biker's hydration system on the CamelBak site, Backcountry properly describes it as both for biking and hiking. Being a huge MULE fan for years, this model is no exception. First, it has more space (not a lot, but some), and it comes in a range of colors, even cheesy colors and colors you would not wear during hunting season. The strapping system is also more advanced, so you don't end up with all this nylon fluttering about. It is, in my opinion, the best overall hydration pack made today. The MULE is comfortable, light (when you need the perfect day pack on your Pioneer Mountain Trinity pilgrimage, just strap it to your backpack for later use), easily accessible (the open pocket, for instance), and exceedingly durable. This model is just as adaptable as previous models, allowing for quick-n-easy packing flexibility depending on the activity. And yes, it's great for mountain biking as well.

I have owned one of these for years! The improvements that have been made over the years are awesome. I love the Ipod pocket. It is ridiculously easy to put your bladder into it. Just unzip the back and put it in. You don't have to fill up the bladder then try and squeeze it into a little sleeve in the back of the pack like the older models.

Everything about this pack is very well designed and great, except for the zippers! The zipper nob comes off leaving a string to tie. It looks very tacking using a tied string to zipper up a otherwise very cool pack. I will not be recommending this to my friends due to defect.

I've used a Classic CamelBak for the last few years because I didn't want too much bulk on my back.
After a month of rainy days here in the Wasatch and not being able to stuff a light raincoat I went for the M.U.L.E, and have been _very_ happy with it. It comes with a waist strap, but I haven't needed it, as the pack feels secure - and most importantly - not too bulky.

I agree with Laura though, about the zippers. Within a week the two tabs have broken off, requiring me to tie a bit of cordelette onto them. It's not a big deal, but that's why I gave this pack a 4 instead of a 5.

Great size bladder for long rides in the mountains. There's plenty of room for your extra gear, a rain coat, tools, yet it condenses down so as not to feel like an over-sized bag. Pretty sweet.