Ex Plumber here but I have been out of the game for a looong time. The tankless heater will cost a lot more up front and installation will cost more. Requires a descaling process preferable once a year. Not difficult but some people will hire out to have it done. My opinion the electric tankless heaters aren't as good as the gas units. They may have improved over the years.
Conventional water heater requires an anode rod replacement after several years. Quite often they never get replaced. Use a water tank blanket to conserve energy and a tank flush annually won't hurt and only requires a hose. In all honesty, I have never flushed my own tank. I know, "Bad Boy".
The rumor about taking longer to get water to the faucet in my opinion is simply the purging of the lines of cold water before you will feel the hot water at the faucet. If the bathroom is 30 ft from the heater it will take longer than if it's only 10 ft from the heater. Same difference with a tankless.
If you take hour long showers and run a tank dry, then and only then the tankless system would be a nice addition to the home.
Good luck!
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