The Stiebel with its Tempra line has moved up to number two this year on our list. Their technology is similar to the Titan and the company has been around for years. The units are reliable and withstood all pressure and output tests.
They currently offer a 3 year warranty on their product line and have some of the best hot water output production in the electric line. The downfall of these units is they can be pricey and have a 3 year warranty. They are also originally from Germany so parts can be hard to come by. They do have manufacturing plants in the USA now so this problem has been alleviated.
The company site is: www.stiebel-eltron.de but the site is in German so we put up the American version as well. There are so many distributors of this product on the internet now that it is hard to keep up!