I am looking to replace a 10 year old Bradford White conventional 50 gallon water heater. We are a family of 4 with two small kids so we take a lot of baths. Also, we have a dual showerhead shower in our master that uses 4 gpm when we have both heads on. Needless to say, we often run out of hot water.

I am considering the following systems:

1) AO Smith Vertex (GDHE-50-NG) - This 100,000 btu heater has a 1st hour rating of 129 gallons and a recovery of 129 GPH. I like the fact that it is energy efficient, can deliver 3.2 gpm (at 60 deg rise) once the tank is empty, and recovers quickly due to the 100,000 btu's. However, I have read on these forums that a lot of pros don't like AO Smith and am also a little concerned that there are a lot of parts and electronics that could break down. The installation cost is probably a little more due to the venting, electrical, and condensate line.

2) Bradford White High Performance (GX-1-55S6BN) - This 80,000 btu heater has a 1st hour rating of 200 gallons and a recovery of 86 GPH. My basic understanding of this unit is that it superheats the water (160 or 180 deg?) and then uses a mixing valve to bring the temperature back down. I like that it has a great 1st hour rating, it is a pretty simple design without electronics to break down, and I can use my old venting. The recovery at 2.2 gpm (at 60 deg rise) is not as good as the vertex, but then again you are starting with a ton of water. I am a little concerned that the mixing valve could fail and that you could be scalded with 160 deg water. Also, I read that the minimum input for the mixing valve is 0.25 gpm. Is it possible to trickle a faucet to wash your hands and not reach this 0.25 gpm?

3) Eternal Tankless (GU195) - This 199,000 btu tankless can deliver 6.4 gpm at a 60 deg rise. I like that this tankless doesn't have the cold water sandwich problem, can give us endless hot water, and is efficient. However, I could see situations where we are starting a bath and taking a shower at the same time and exceed the 6.4 gpm. Then there is the cost of adding 40 ft of 1" gas line, and more parts to break down. I also read some very mixed reviews of this on Amazon.

At this point, I am probably leaning towards #1 or #2, but I am not sure. What do you think? Are there any other models I should consider?

Thanks so much for any advice!