I've kept both.
I used columbians as dithers for medium sized cichlids. they are great fish, Mine lived to be about 5-7 before they dropped of old age.
Serpaes are like 1" piranhas and will rip a fly to shreds if you drop any dead insects in the aquarium, fun to watch but can be mean to tankmates
As an interesting alternative, why not try Black Phantom tetras.
I have a group of 7 right now in a planted 20g.
theyre still small but right now but theyre beginning to show some real beauty, a pretty uncommonly kept species.
The females are a sublte red whilst the males are blue black with large anal and dorsal fins that make them almost boomerang shaped when they extend them. Males have an irridescant blue spot on their side.
They are in the Serpae family of fishes, they arent huge *******s like serpae tetras.
If you like serpaes but dont want *******s that will nip everything and chase other fish if not kept in a large enough group, give the phantom a try.
There is even a red phantom tetra
