My coach came with a Girard Gen II and it works fine. There are two things that help me get a good shower from it:
First, I am careful to avoid an excessive water flow at times when the cold water is truly cold. The heater can't keep up and it gives a cold shower. Also, note that there is a control knob in the medicine cabinet to allow you to increase the basic heat of the Girard Gen II.
Second, I installed a temperature-controlled shower faucet, which is different from (and superior to) a pressure-balanced faucet. I discussed this in one of my first posts on the Forum:
https://www.forestriverforums.com/fo...er-119716.html
I've heard of enough problems people have with the Atwood and the Truma that I wouldn't dream of swapping out my reliable Girard Gen II.
–Gordon