Advice - Tankless Water Heaters

[sandy2982]

I'm interested in replacing my water heater with a Bosch
AquaStar. It would serve a home with 2 baths, and an in-law unit with
bath and kitchen.

I have found these two models at tanklesswaterheatersdirect.com and wanted to know if anyone had any experiences with either one?
The smaller model ($500) says it provides hot water for "one major application" at a time. The larger model (close to $1000) provides for two and a half.I'd welcome hearing opinions about this heater and about sizing.
Thanks!