They always look nice and shiny when wet
They don't perform so well as they get too hot with out going round them, does look better on a house thoughThere are some fancy solar panels about now, i saw some yesterday that were built into the roof and had been tiled around. Saved on tiles.
you must use pure water otherwise they will scale, a pure water kit to do any amount will start about £6KIn future I'd think hard about a ground mounted array. The cost of contractors to clean can mount up. With a bigger scheme (Ours is only 26 kwp) it would be worth buying our own brushes.