The Neomeris isn't bad and grows rather slow. Consider it a type of Coraline Algae (though it's not). The other one on the other hand is a double edged knife. If it is Bryopsis, it's a real pain to take care of and is very similar to hair algae. If it is Caulerpa, you can keep it pruned because it is a macro algae and be able to use it in the same way. But, in a display, it can quickly grow out of control without proper care. Once it takes over, it can be difficult to find something that actually wants to eat it.