A tank-less will work long as maintenance is followed and if water has mineral content is addressed. Need to descale heater depending on use once a year to every 3 years. At 10 years it likely a brick anyway cost of boards,blower motor,sensors that's assuming parts can be had. I wouldn't put 250$ + in parts in a 10 year old tank-less anyway. trash it and get new. figure this cycle every 10 to 12 years
((ALSO read the gpm gallon per minute flow rate specs you average shower head new no drilling out flow screen 1.2 to 2.5 gpm the ever so loved 6" to 8" round rain shower head everybody wants now 4 gpm if lucky more likely 5 to 6 gpm faucet uses 1.0 to 2.0 gpm. you add body sprays add 1.2 gpm per body spray.
Pros limitless hot water as long as it works fine and maintained highest efficiency
Cons Cost of tank-less and install seeing its a retro fit job, maintenance and yes the fuel bill
The old tank type whats there already so shouldn't need to fuss with much in pipe work to change. Long as the gas and water continue it works.
Pros simple install generally no fuss after install
Cons takes up space limited hot water depends on tank size and water temperature. 10 to 12 years average life cycle always leaks at worst time and dies on weekend or day before.
Power vent water heater you have storage of already heated water quicker heat up. Can side vent if needed.
maintenance keep intake and output vents free of bird nests trees etc no air no hot water. Need to size/run venting as per installation guide.
Pros faster recovery time for heating back up better operation cost
Cons bigger then usual tank type adding blower and related controls, sensors costs more again likely rework of piping to make fit in current space. No power no hot water. sensor failure anywhere on heater ie blower motor, pressure sensor, temperature sensor or board/control. You didn't follow install instructions vent problems no hot water.
To be fair you don't always get every problem possible with each heater type some get lucky beat 10+ yrs and then its gambling time.
They all look over at me As a 5th generation plumber in family tree and was 4th generation in family business until 2008 i have seen ,heard every story about water heaters and there issues.