I was just going to ask the same question, but what I'm more concerned is feed back as in what people think about their brand.
Water heater with tank, have storage of water which is at a constant temperature, flip side if the usage is high then the last one in the shower might get cold water, if it can't heat up water fast enough.
With tank-less water it is a on-demand system, where water gets heated up right away, this system is more efficient but cost more.
I'm planning on replacing my water heater in the next week but still haven't made up my mind as tank-less / on-demand costs more.
I also want to mention I like the idea of tank-less water heater because they use less space, less junk in my basement the better it is! (more room for my junk..hehe)