For several years I have been using green debris netting over hoops to cover my plants (mainly brassicas)as have many people on our allotment. It's easy to put up, particularly in a strong wind,stops all bird damage and supposedly stops butterflies laying eggs-although I have not found this always to be the case!It also gives some degree of wind protection and can create a warm micro environment that helps to bring things on a bit.
However it is a very tight weave and I think it does block light off. I have had trouble with some plants growing poorly I suspect because of reduced light. Also obviously if you need insects to pollinate your plants you can't use it.
What are other peoples experiences?