My wife bought me a set of O2 rain gear for my birthday. The waterproof lining started shedding within a month of occasional use. Both the jacket and pants now leave a trail of white plastic flakes, causing a mess in the house as well as clothing. (Don't wear this to work.) Also, both the jacket and pants tear very easily. I've had $5 disposable rain parkas last longer than this.
This is my second pair of O2 pants. You sort of get what you pay for and you sort of get more than what you pay for. They do an amazing job of blocking rain and keeping in the heat. However, they are rather fragile. I ruined the first pair while on my bike and going too fast past some blackberry bushes. They tore right through. So...if you're careful...these are amazing for the price. Last, these sizes run kind of big. The first pair I bought were Medium, the second were Small. The Small's still fit over my pants and slip over my shoes.
I got these along with the O2 hooded rain jacket. These are perfect if you are looking for very lightweight rain gear for cycling. Be warned, however, that they run very large. I'm 5'8 and 125 lbs, and the medium is enormous. I had to re-order the small, and I'm fearful that even that will be too big. The tree fort representative told me that small is the smallest size offered.