I'm starting to investigate replacing my gas water heater which just celebrated its 24th birthday. I think it's time. What are some important things to consider?

Current water heater: Rheem, 75 gallon, natural gas
While I'm quite comfortable with technology, I much prefer the old, tried&true control systems. I really don't need to adjust my hot water from my phone.

I have a hot water recirculating system that uses thermal convection (no pump) to speed up delivery of hot water to my upstairs master bathroom.
Do the new heaters have built-in heat traps (which would disable my recirculating system)? I'm less concerned about efficiency than performance and reliability.

What brand(s) should I narrow my focus on?
What do the new 2015 NAECA standards mean to me? Larger? Different hook-up? More finicky?
What questions should I ask of a potential installer?

Mark made some great points in this post. I noticed Rheem wasn't in his list.

Thanks in advance for any advice.
WallyH