I think they're great too, but the ones we've got don't give out much light - they are more for decoration and indicating the path etc rather than lighting as such.
They vary a lot, some have orange light, some blue, and the newest ones talk about white light, but are still not very bright - just don't want you to be disappointed!
I think that your best bet would be to visit your nearest DIY store or garden centre, and see what advice they give.