I had a 55g reef tank running for 9-1/2 years and currently a 12g nano for 8-1/2 (both mixed reefs). The differences between these two 'natural' systems (only live rock and live sand) isn't so much in the setup (other than larger everything for 55g), but mainly in the approach to maintenance. With the 55g, I could get away with 10% water changes every few months (if that), but the nano gets 5%/2x week, consistently. The 55g had the shallow sand bed and sump vacuumed maybe 2x/year, the nano once a week, every week.
Although the nano requires more frequent care, the size and volumes involved are small and easily manageable. The opposite tends to be true for a large systems. Whether small or large, each is challenging in it's own way.