I currently run a 33 gallon tank that I love but will eventually upgrade it.
Things to remember with smaller tanks
-definitely cheaper to run than larger more complex tanks
-don't require a sump system can get away with hang off the back skimmer
-get crowded with equipment real fast
-depending on what you want in both critters and fish creativity is name of the game
-require frequent top ups due to evaporation loss(I top mine up 3 times a week in between weekly water changes)
- if something's goes wrong things will tend to go bad real fast (fish dying, coral dying)
- depending on your bio load might have to do daily cleaning of tank glass(I have a heavy load 7 fish 2 peppermint shrimp and lots of CUC spend about 10 mins a day cleaning glass and skimmer box)
-limited to the size of fish and types of fish you can get especially where aggression issues come into play
-same goes for corals
-tank parameters can be more difficult to maintain although I haven't had any serious issues on that end with my tank
Whatever you decide to get enjoy it don't have regrets as regrets tend to empty your wallet real fast
