In a complete vacuum this is very close. Each does certain things the other doesn't and you certainly get a great PG either way.
However, as it is not a vacuum, I say not. First, I wouldn't want to mess with chemistry in the middle of a championship drive. Second, I believe that Rondo is he perfect point guard for this Celtic team.
If you asked this question when the big three era was over, I might have a different answer, but for now, and quite possibly another 2 or 3 years, Rondo is my man.