I have the cataire screens and am very pleased with them, the mesh itself is unobtrusive. I have every faith in the screens although they haven't really been tested as Tiggy is an OAP now and more interested in sleeping than escaping through windows! You have to make the frames yourself from the kit supplied but they are fairly easy to make although I got my sister to make mine as I am DIY dyslexic.
You can also buy the mesh seperately and I know that some people on CC had made their own from mesh and heavy duty velcro without a frame.