Some review of this bag said it stunk and they couldn't use it. Yes, when I opened it, it smelt strongly of new plastic. I opened up all the compartments and let it air out for a couple weeks before putting any of my belongings in it. I wanted a nice large bag for a small price to take to the hospital with me when I go into labor, and a bag that stood out and said "Im HER bag, don't let me be left behind anywhere!"
As for being made mainly of plastic, it seems like a well put together bag. I don't think it would stand up to tons of abuse, but for mild usage and needing lots of space this is a great buy. If you expect a bag to come smelling like anything other than plastic, don't buy a plastic bag. Also, if you think this is going to stand up to regular usage and being dragged or tossed, I think you may end up irritated when you find a rip.
The zippers all work great, and this bag really is huge. I think Id have fit plenty in a 19" but the 22" is nice :)