I found the waterproof pouch to be really effective at preventing leakage onto the soft fabric cover, even of poo. The idea is that if the cover doesn't need washing, save the energy but if I'm going to the effort of washing the pouches, a few small covers isn't likely to make much of a difference. I also found the pouches quite fiddly to snap in and out so decided just to leave them snapped into place all the time. The biodegradable inserts were really impressive; very absorbent!
I'll admit that I wasn't entirely sure which way round the little gPants were supposed to be worn. Most of the pictures on the site look like they are the other way around to the way I put them on Holly! Holly seemed very comfortable in the gPants.
The biodegradable inserts for the gNappies works out at about twice as expensive as traditional disposable nappies but if you use the cloth inserts at home them the costs would drop significantly.
I will admit that I have not been converted to using gNappies when out of the house. I thought they were brilliant for wet nappies but for dirty nappies the waterproof pouch got dirty and so I still needed to carry the mess home with me!