One of my most favorite strollers. I bought the stroller because, first of all, I fell in love with its design. It's really beautiful - much more even than in the pictures. Many moms stopped us to adore it and asked me where I got it.
One of the best things about this stroller is its driveability - despite the smaller-in-size wheels, we have passed through every kind of terrain. It doesn't have an "old-school", spring suspension, but the L-shape of the chassis makes it flex and, thus, shock-absorbing. The wheels did not get stones in their foam over time - I consider this to be a sign of their quality. There was no problem to tackle grass, bad terrain, downhill with bumps or pup the stroller up a curb. Only when I changed this model for a Valco Snap, I realized how wonderfully it pushed that I did not even notice pushing it. The Valco stroller I got was a disappointment for me after owning the GB Zero because that driveability was just unmatched (by far).
The mesh seat was perfect for the summer, and it came with an included seat liner (pad). Here, I would complain a little that the liner did not hold in place that well, sometimes I had to put it back up since it slid down a bit. The seat unit is non-reversible - fixed in the forward-facing position, but the little one was comfy in it and did not complain, even though he was around 9 months old. He fit easily and had enough space - even with a footmuff; the seat is super spacious. The canopy can be extended with a mesh section that you need to unzip - it also serves as a viewing window to see your little one. The basket is shallow and small-ish, but I could reasonably load it with enough shopping when needed. As the stroller is quite stable, there was no problem to hang one or two bags on the handle - so trips to the shop were really not a problem.
The dimensions after folding (it's super flat!) are fantastic, so compact that you will fit the Zero anywhere, in any car boot, between the seats... The folding system, however, needs some getting used to - I didn't mind it after a few tries, but my husband didn't like it (and that's why we changed strollers eventually). I must say I missed this one from then on.