Which is better – solar flat panels or evacuated tubes?

I am often asked about the difference between evacuated tubes and flat plate solar panels; people want to know which is better and there are some confusing websites out there, particularly those which extol the virtues of evacuated tubes, so I shall let you have my views on each type of product. You will have to bear in mind my own bias; after some considerable research I invested my own money in a flat plate factory for Genersys; I personally decided my preference and the reasons have not changed in the past eight years.