Go Green - Who makes tankless water heaters?

We installed a Takagi (gas) tankless water heater when we did our kitchen remodel 3 1/2 years ago. The main reason was that our house is older and our water heater used to be at the end of our galley kitchen. We wanted the space. After installing it (on the outside wall to our kitchen) it’s been fantastic! We NEVER run out of hot water and it only heats water when it’s needed. Make sure that you get a tankless that can handle the water flow (gallons per minute) that you’ll need. The smaller (Bosch) tankless water heaters at Home Depot weren’t going to be able to handle our whole house. I think they’re primarily for additions, apartments or very small homes. We mail ordered our Takagi for $995.
takagi.com

Got a Noritz 631S Tankless gas heater for my home, which has two bathrooms. It replaced a 50-gallon traditional heater, and so far, works perfectly, even when multiple users in the home are using hot water (such as two showers at once).

I have a bosch unit in my house. If you read the documentation, the bosch units are built by Takagi.
Anyway, I am very happy with my unit besides 1 thing.
When you first turn on the water, you will get the room temp water that is inside your pipes first, then you will get very cold water that hasn’t yet been heated by the burner, then when the burner is in full function you will get hot water.
What this means in reality is that for showers and washing dishes, this thing is awesome, but for the occational hand washing in warm water, you just wont get it in time.

WaiWela is another great tankless water heater. There are a lot of safety features that are not found on other units. Check out http://www.lowenergysystems.com.

Any rebates for tankless water heaters?