While not an expert

I can definitely give you some info based on personal experience and info learned from others.
Reef tanks are tons of fun for most people. You need to be dedicated to your tank to make that statement a reality. You have taken the first step to having a successful reef tank as first and foremost, READ, READ, READ lol. Nowadays you can find just sbout anything you need to know right at your fingertips. As for time consumption..... It really depends on what type of tank you want. If you stick with mainly photosynthetic corals you won't have to mess with the tank quite as much. The more corals and fish the more you have to ensure that your water stays within all the proper parameters (ph,alk,salinity,CA,etc) as it becomes easier for big swings to take place based on the bioload your animals add to the system. You can have a successful reef tank without spending tons of time doing so or without all the bells, whistles and custom systems sometimes associated with reefs.
I am a believer that the bigger the tank, the easier it is to keep good water parameters. The thinking is that with a bigger tank, there is more room for impurities and the likes that cause havoc in a reef system. In smaller tanks little changes show up fast because there is less water. I will never personally own a tank smaller than 75G unless its plumbed to my main tank.
For what it's worth, I had mine halfway in a wall cut out and hated it, never could do things from the back side of the tank and on a 75 or larger it can be helpful to reach all areas easily. Now, I have a sump and a Refugium and will never have a tank without them, they are life saving insurance policies if put together correctly IMO.
Hopefully this is a good start for you and I'm sure more will chime in, regardless...... Good luck and welcome to R2R