What I don't understand is why some people are so vehemently against them. If they work, then great, if not then oh well.
I do find the idea that just because nobody has got them to work yet then we should never try again very stupid.
They have been trying unsuccessfully for nuclear fusion for a long time, but it might just be worth the effort eventually.
The first attempts to found a colony on the Americas failed, but they worked out eventually.