The tech on tankless is pretty close to perfected now. I went tankless 6 years ago and have never ran out of hot water. There is the obvious space savings too.
I have a Stiebel Eltron Tempra 29 Plus. They make a whole series of course - but with a family of 6 and lots of water usage, coming in cold from well in MN, we figured $150 extra was worth it for this model. The base model like 24 or something is undoubtedly fine for most applications - especially in the South or with smaller families. They also make point of use devices and you can put 4-5 throughout the house - they are cheaper and require minimal electric.
Install is SUPER easy if you have any plumbing skills at all - even if you don't, it's probably a 2-hour service call. It's simply mount and run the pipe. From there depending on model electric is straight-forward and instructions are very well done. The only thing to consider if you do go with a larger unit (not size, but capacity) they run on 200 or 300 amp service - you'll need up to 6 50amp connects available - that is some heavy duty wire and most boxes won't have that kind of capacity spare on their box - so that's the only real consideration. My electric install took about 4-hours and had to add a 2nd breaker box, but it's been WELL worth it. Again - have never run out of water. It heats on demand in about 7-12 seconds (7 seconds at faucet nearest tank, 12 seconds at upstairs sink at end of run) and it goes forever.
Maintenance is minimal. In my case...none. I'm supposed to unhook an intake coupler every 3-4 years and remove any hard-water build-up, but I opened it up once at the 3-year mark and it was day one new - so I haven't checked it since then.
You'll pay about twice as much up front, but after that - it's just savings and non-stop hot water.
