Ive had some solar powered stake lights (bought from a pound shop) in my garden for about 6 months now. Most of the time they all work, but there are times (when its not been such a nice day) that some dont. They dont give off any real light. They are more like little stars in the garden than a way of illumination.
I also have a PIR security light which is solar powered (bought from Solar Security Solutions - Protect Your Property) which is great. Its very bright and works perfectly. A real contrast to cheap stake lights I have.

Alex