I decided to replace a rather tatty fluorescent strip light in my utility room with a new one. Saw a nice one with a diffuser in one of the sheds - quite attractive with electronic ballast.
Got it home and fitted it and was appalled - very poor output as the tube is fitted tight up to an open channel extrusion which holds the wiring and the control gear. This means that all the light from the top two thirds of the circumference of the tube is wasted illuminating the inside of the fitting.
Will be going back to the original one which had the tube 10mm below a white enamelled panel which served to reflect the light and didn't block any of the light.
Just shows that attractive design isn't always effective.