Quantitive easing.

This seems a really good thing for the banks. What are the assets that the BOE is buying? i presume they are being sold at a profit. They are not cdo's are they, that can't be sold in the market. And what is the deal for the taxpayer? I read that the Japanese tried it some years ago and it failed. Is any other country doing it? If all it is doing is generating profits for the banks at taxpayers expense then it should be stopped. The whole thing is very confusing.