I think the easiest system to maintain is the largest system you can afford to set up right. The smaller the system is the more fragile the balance is. A 100 gallon tank will be much easier to care for than a 24 gallon tank if it is properly equiped. Alot of the difficulkty has to do with the way you have it set up. Auto top off, semi-auto water changes, CLSs, the right skimmer, preparing the tank before stocking,
calcium reactor, electronic monitors, ETC... all these things can make a system much easier to care for and maintain properly.