I installed my own Tankless heater, and will give it a 7 out of 10. The biggest issues i have run into is that gas, water in and water out must all be 3/4 inch. This wasnt a very big issue as I had 3/4 on the ceiling but they reduced it down so i just replaced the 10 or so feet of N.G. pipe to all 3/4 inch. Next is venting. When i got my unit at Menards I was told i could plumb it out the chimney just like our regular tank heater was. WRONG. I was getting backfeed through the furnace, and co2 monitors kept going off. Relized the problem and then vented out the side of the home, no issues since. the system does take a little to get used to such as using small amounts of water for shaving or brushing of teeth, if the faucet isnt opened up enough the system wont detect it, and wont heat, thus you get only cold, however if you multitask when another appliance is using hot water or someone else showering, you dont notice this. We have had out dhishwasher, cloths washer, and both my wife and I showering and never ran out of hot water, yes the pressure was reduced but hot water was perfect. I think the biggest thing is going to be getting pipes line up and soldered. if you can get your main water shut off, and not have that occasiona drip that most lines have, you should be fine. I would suggest that you get those flexible hoses instead of trying to plumb it in with stick copper, get the water heater flex pipes and it will make your life much much easier. If needed i can send photos.