Regarding the comparison to a fanny pack in the front, there are obvious differences.

A fanny pack in the front is cumbersome if you've got any activity going on that's greater than a stroll. For example, I can imagine myself snowboarding with a Ribz, even though it would not be desirable. In contrast, snowboarding with a large fanny pack in front would be substantially less fun I think.

The weight distribution is totally different. A Ribz calls for shoulder and back muscles pulling backward to counteract the weight of the Ribz. In contrast, a fanny pack is mostly supported by the hips with some input from the lower back. I think I would prefer the weight distribution of a fanny pack because hips are naturally built to carry more weight. At least my hips are. A fanny pack in front hits a sweet spot for me. I can carry weight all day right there without it fatiguing me. However, I doubt I could get as much stuff in a fanny pack, as compared to a Ribz.

I'm not totally sure about my theories here without trying out the Ribz. I'd want the Ultralight Model, but I'm not motivated to buy it right now.