I needed a new raincoat because my old one had disappeared, but didn't really want to spend a great deal of money in case the old one turned up (which had cost me quite a bit and was a really good coat). I thought this one seemed cheap and cheerful but honestly didn't expect much - I know other people that have bought "Kag in a bag" style raincoats which have been leaky and not worked very well and I thought this might be the same kind of thing. But this has actually been great! Just as good as my old raincoat, it's kept me dry and is also a good wind breaker too. As someone has said before, the hood is a bit small but it's not really a big issue.
For sizing, I'm about a women's size 10-12 and bought a Small, which is a perfect fit :)