Hm, i think its a question of your personal taste ...
I like rubra because they are, compared to Lasius niger, a little bit bigger, the red color is kinda unique, they have a sting, some people think its cool, because
they are superior to other ants - in my opinion thats a stupid argument .. but, as i said, some people just like the feeling that their ants kick ass

(such people should buy Myrmecia pavida^^ *just kiddin*)
They grow fast, they are easy to handle .. except of the sting, it can hurt if you have to work inside your arena .. so .. its a really nice Ant.
On the other hand .. Lasius niger would be sth new to you, that could be nice too. They also grow fast, are easy to handle etc., different color .. monogyn not polygyn .. they dont need
anything until the first workers apear .. it really depends on what you like.
Have you ever thought about Formica fusca? They are pretty big and the colonies stay small. But Antstore reclassified them from difficulty 1 to 2 .. i dont know why, if you are interested i would ask whats more difficult with fusca than with rubra or niger.
At the moment, im keeping a Lasius flavus colony, lets see what happens, i like the color and their shape, they are just too cute
