Be aware of what you are actually paying for.
Let me start by letting you know how we found these guys. My wife had helped out one of these guys by giving him a jump start and following him back to his yard. The guy gave my wife a card and was very thankful and pleasant to her.
Since my wife had the pleasant contact with the tech from GTC, I figured I would give them a call. I explained the issue to them, and what AO Smith said. They told me the warranty would not be an issue with them. I was happy that they could get a tech out the same day. So the tech showed up, very nice guy, very professional looking. He looked at my water heater, and said this was one he could not work on. He told me I would have to get a specialized guy to do the diagnostic work. This is where a light should have come on inside me, but I thought, ok he's honest about not knowing these, and this looks more like a electronics issue. So he gave me a quote of $96 for a diagnostic service call. I figured any plumber would charge me this anyways, so I paid that.
The next morning, GTC came to my house, (just so you know this is day 4 without hot water). Once again the tech was very nice, professional looking. I took him to the water heater and watched him work. He did a through job diagnosing the issue, asking me questions about environmental factors and such. So his diagnosis was the electronic control panel on the water heater. So he went out to his truck to call the office and work up the quote. He then came back with a quote of $460 (just another FYI, this was their VIP pricing, since my wife had helped out on of their tech, they offered this discount to us as a nice gesture). I was a little shocked, but figured this must be a pretty labor intensive repair. So I agreed to the quote.
He then took apart the control panel from the water heater, which took him about 15 minutes to complete. (FYI, I was there with him). He then headed back to his office, he said he had a bunch of work to complete, so that the part would be covered under my warranty. So about 30 minutes later, he returned with the new part. I was excited to see this, I thought for sure I would be getting the call they had to order it. So I watched him install the new control panel. This took him about 15 minutes to complete and fired up the hot water heater.
I was excited to have my water heater working and said good bye to the tech.
It wasn't until later, I really started to think about this cost; ok he made an honest mistake and accidentally charged me for the part that was covered under warranty. So when I got home from work, I contact GTC. I explained, that I think I was charged for the warrantied part by mistake. He said he would check into it and give me a call. He called me within a few minutes later and told me that I was not charged for the part and that was the cost of the repair. He told me the tech was here for 2 hours, I will give him the benefit of the doubt with rounding here. So I asked, you charge $460/hour for your service? (Since I already paid the $96 for the diagnostic, so this should not be chargeable time.). He would not really comment on that, but just said the cost of the repair was $460 (plus taxes). So I asked him, you charge your "VIP" members $460/hr? (remember, I already paid the $96 for the diagnostic and the repair itself took less then and hour). He would not comment on that.
Now I do take responsibility for agreeing to this cost, it is my fault that I did not get all the detail, and assumed that this would be a very complex repair.
If you do ever decide to use GTC, the techs themselves were great, very personable and conducted themselves very professional. You need to be sure to get a complete break down of the quote. Ask them for time estimates and what the per hour charge will be. Learn from my experience, do not accept their "per repair" estimate, question everything.
I would highly recommend getting a second quote from another company before committing to a repair with GTC.
I hope my lesson learned benefits you in the end.