Damn, for that kind of money, I'll travel around the country and install them. For someone even "semi-handy" it shouldn't take over 4 hours.
With the electric, especially if you're a novice, label your wires when you unhook them. Shut the breakers off (and make sure there's no current to the HWH. That's a biggie.
Once you get the new HWH in, drain it from the bottom about once a month. That'll reduce lime build up in the tank and on the elements, to some degree. Just drain off about a gallon. I think you'll get more than 7 years out of it.
(I bought a place once that had an elec. HWH and it had gallon buckets of lime build up in it. Ended up just replacing the whole unit.)
RE: What's wrong with being a frog?
I'm not recommending it.... I just thought I'd heard that~~~