This is an impossible question to answer with any amount of certainty, because all people are different. In other words, there are so many variables that I doubt that there is a standard way to answer this question. So, here are some points to consider.
First, if a person is ambitious, then a person with high abilities might want to go to a big firm. In other words, he or she may want to be a big fish in a very big pond.
Second, with this point made, not all people are ambitious in the same way. For instance, a person might want to have a quiet life and pursue other things, such as spending time with the family. In light of this, a person with high abilities might want to go to a smaller firm where the work load is more manageable.
There is another possibility, the small firm may be the best at what they do. So, a person with high abilities may actually want to be there for this reason.
In short, as you can see, there are many variables.