I had a Rheem hybrid electric 80 gallon installed 2 weeks ago in our garage and I would be very reluctant to put one of these in the attic. Efficiency wise it is working as expected and my natural gas consumption has dropped from 1.0 Therms/day to 0.08 Therms/day (just our cooktop and clothes dryer are using gas right now) and the electric use has been on target with my estimate at 3.2 kWh/day. Gas was costing me around $1.90/Therm and I'm giving up about $0.06/kWh in credits as a net generator, so $1.75 vs $0.19 is a savings of $1.56/day or $569.40/year.
Now the bad part is that a hybrid heat pump is noisy. I think that the Rheem has the lowest noise level on the market at 49dB, but this is still generates a very noticeable low frequency hum/drone/vibration and it will run for 2-3 hours to replace the hot water that was used from a shower in the preferred Energy Saver mode. My spouse is definitely not happy about the noise level. It does appear that over time we are starting to tune it out, but I can't imagine having this over a sleeping area.
One of the most important considerations for the recirculation system is that all of the hot water pipes going out are well insulated as well as the return pipes to minimize the heat loss. If you have the ability during construction make sure that this happens. I don't know if there is way to insulate pipes that might be in a concrete foundation, but if there is I would do that also as I think I am losing a lot of heat that way.
I also now have WiFi plug on the recirculation pump and I created an Alexa routine "Run Hot Water" to acknowledge the command, turn on the pump, wait 4 minutes, turn off the pump, and then announce that the hot water is ready. This has been working great.