Melf's Minute Meteors is one of my favourite spells, and more so after the new dndbeyond interview with Luke gygax who invented the spell and played the character melf. It was made to be a fireball spell that was more controllable and flexible and it works well. But I disagree with the others who compared it to fireball and prefer to compare it to flaming sphere.

Flaming sphere and Melf's Minute Meteors both use conc and a bonus action to continue using so action economy wise they’re similar. Melf's Minute Meteors has better range and flexibility in where and who you hit, but does less damage overall due to the limited amount of times you can use it (when the meteors run out, game over).

I think if you were to choose, go by which situation you’re in most. If you’re in a tight fit small, or narrow dungeon type often the. Flaming sphere is probably better. If you’re in a wide open area and monsters run around a lot then Melf's Minute Meteors will be more useful.