I don't know anything about how the Gdiapers work.
We use cloth and are very happy with it. (Used it for my son through age 15-months and are now using the same diapers for my 2-month old daughter). It means 2-3 extra loads of laundry per week, but otherwise is very low-impact. There are a lot of choices out there, which can be overwhelming. We use "fitted" diapers, which are probably the most cost-effective besides prefolds. (And they are shaped and have snaps, versus needing to be folded and pinned, so they're less intimidating to cloth diaper newbies). You do still need a waterproof cover for these, but you can get away with 3-4 covers and just let them dry between changes by swapping them out. Other styles, which are more expensive, include pocket diapers and all-in-ones (neither of these need a cover). We also used "one-size" diapers for a long time with my son - these are like fitteds *usually) and have snaps so that you can fit them on babies that range in size from 8-40 lbs - basically birth through potty-training.
I have several other posts on Mamasource where I describe what I personally use and I'm happy to give you the details if you're interested. With the cloth, you generally recoup your investment in 4-6 months, depending on how much you spend up front. Another bonus is that most cloth diapers have very good resale value, so you can sell yours online for around 50-80% of their orig. value (or better yet, buy some used - that's what I did) when you're done with them.
I suggest reading the reviews at www.diaperpin.com and consider purchasing 1-2 diapers of the couple styles you're considering to try out. Then you can get more of what you like best. Or you can just take the plunge and buy a stash of whatever someone you trust recommends. This is what I did and it worked out pretty well for us.