I use the system when I'm going long fast rides (100-200 miles) in hot weather. It is fast to refill and is out of the way. Works great! I also use it for time trialing since it's out of the wind. I use to slip a CamelBak bladder into my skinsuit, but it would move around, which is entertaining, but not real good for maintaining focus in a TT! Would be nice if it had a bit more room for tubes & CO2, but my biggest gripe is getting the thing open. I must have t-rex arms from riding too much because the lid seal is a bit stiff. Other than that, I love it!
The Iris cage is sleek and sexy, and gently flexes to hold a variety of water bottles. I use stainless Klean Kanteen bottles, that rattle in other cages and are held securely in these. Made in USA, steel is real. LOVE these.
I find these waffles a lot more satisfying than your typical gels (and even most bars), but they are a bit bulky in the jersey pocket. If you're only going to carry one or two, they're a nice change from gels and chews, but if you're doing a long ride, it's hard to carry enough to get the calories needed.
I'd definitely recommend them as a nice option to other products.
I was really surprised by how well these work, and the underlying rationale on the science behind it was discussed in an article in Velo News in the Spring (myths about lactic acid-lactate). I was initially thinking the effectiveness was largely a placebo effect, but after several rides (most hilly) I was impressed both by a sense of having more power-endurance and, more dramatically, far less soreness post ride.
Take 3 pre-ride as per label and try to take one per hour (when hands can safely get free!).
Overall I would at least recommend giving them a try and see what you think. A thumbs-up from me.