Cheato is fairly easy to maintain, and when the conditions are right with flow light and nutrients it grows really fast. It isnt invasive covering surfaces and becoming nearly impossible to get rid of. When conditions arent right it either dissolves slowly or fragments.
Gracillaria, pretty much the same as cheato, but is a little more challenging to maintain. I havent quite figured it out yet.
Caulerpa, very adaptable, grows very fast, is invasive and can be a real PITA to remove once it becomes established in LR. Some species have been banned in some areas of the US, because of its invasive nature. When conditions arent right it sporulates ( goes sexual ) this can happen quickly, and water quality can suffer very quickly. Caulerpa also contains a toxin called caulerpenyne which can have adverse effects on tank inhabitants. Activated carbon should be used in conjunction with caulerpa.