Bosch dishwashers: 500 or 800 series? I'm in the market for a new dishwasher, and have narrowed it down to Bosch, I think, but am still confused about the big differences between 500 and 800. I definitely want the 3rd rack, so Ascenta and 300 series are out, and I don't need Benchmark level. So - 500 or 800?