tankless hotwater heaters

so i have to pick my tankless hotwater heat. i am trying to decide between the tagaki and a the rinnai. also between one that is kept outside or inside.

if any of you have any ideas, please let me know.

if you aren't familiar with what i am talking about, check this out from greenandsave.com:

Heating the water in your house accounts for about 11% of your annual energy costs. Consider a 'flash' or 'tankless' model that can save up to 50% over conventional systems . Tankless initially costs about twice as much as a gas system, but the payback is quick plus you get 'endless' hot water, because it flash heats the water as you use it.

The old concept of keeping a tank heated up to 140 degrees all day everyday is rather inefficient given home use is often concentrated in morning and evenings, rather than the middle of the day. Basically, we may like to eat pasta, but it doesn't mean we should leave a pot of hot water boiling on the stove all day...

On-Demand systems cost between $400 and about $800 depending on the volume of hot water that you may need. The Europeans and Asians have used these systems for years, and improved the technology along the way.

The ROI (return on investment) Calculation is based on a system that produces 7 gallons of hot water a minute - enough for two showers and an appliance such as a dishwasher or clothes washer to run simultaneously. If you are already considering replacing your hot water tank, the you'll save even more because you can put the money towards the On Demand system.

also you should know that the silver one on the top is: 10"D x 14"W x 26" H they are all about the same size. this means that you get to save all that room from the hot water heater...SWEET! smaller mechanical closets mean more living/storage space.