So how much is a "reasonable" time for HWH vs Tankless? It can take 20-30 seconds for hot water to reach my upstairs master bath anyway....

Timed the water in my BR today. Took 60 seconds to get hot. "Traditional" water heater.

It may take another 15-20 seconds to get there with a tankless unit. Waiting that long just to wash your face in the cold morning can be a long time. I am spoiled because I design and install these creature comfort items for people all the time, so its a must have item for me. An animal chewed my thermo switch on our recirc. pump a couple of years ago, so hot water was not recirculating in the system constantly. My wife would let me hear about the long 1:15 wait. Once winter came around, I knew it had to be fixed or else... Thankfully it was only a 15 min fix.

If your hot water pipes are in a crawl space or basement and are not insulated I suggest you insulate them. Every little bit helps.

My experience with a Rheem tankless gas unit.
Unit was 6 mo old when I went to Florida for 4 months. Upon return it wasn,t working. The Rheem 800 number says count flashs of internal diagnostic and send part. My installer installs part not fixed call again send another part and their local people to install it. Still not fixed . Rheem authorized a new complete unit finally fixed. I was without hot water for 8 days and the unit was fully warranteed. Parts only after a year.
I have a direct vent tank gas unit today in a different house. No moving parts ,no exhaust fans gravity exhaust thru the side wall. I have not seen any change in my gas bill and outlet water temp is more stable. than with tankless.
If it breaks down parts are available locally, not 2 days away by overnight delivery.
I wouldn,t risk tankless again unless I had no other option.

Many mfgs are getting into the game because they are loosing out on the sales from their tanked water heaters, so they re-badge then for sale from some Chinese mfg overseas. They have been using them in China for a long time. Takagi is all we install. My plumber thinks I am crazy and pay too much for them whereas a cheaper unit will do. People look at value (can't blame them). For example, almost all other company's units come with a remote thermostat controller. Takagi does not and you have buy them separately. Their parts are quality made, not Chinese junk. Rinni is another good heater. I hear this from my plumber. Over the years, I may have install 15-20 Takagi units and have had no issues at all. We are not a plumbing service, and so not just install heaters, we only install them for major remodels that we are involved.

went to put salt in my softener today only to find water under my second AO Smith gas water heater in 10 years. Are AO Smiths as good as it gets?