Installed a Bosch around Christmas. We installed their biggest NG unit available. Says it will run up to 3 appliances. It works really well. Takes a little longer to get hot water on the 3rd floor, but its not a big deal to adjust to it. Also, if you are showering and someone uses hot water at another place in the house, you might notice a change in temperature until the unit adjusts the heat to the flow. Small but notable issues. If you are researching the price, consider another approximately $400 added to the installation cost for the stainless exhaust pipes and the copper you will need. It takes up much less space then our old 40G tank and hangs on the wall, freeing up much needed space in a storage room.