(1) I'm going to go see Mary about this.
(2) I'm going to go meet with Mary about this.
The important question is this: Whose idea was it to have the meeting? In both examples, it is ambiguous as to who first thought of having the meeting. But example (1) is a little less ambiguous. In example (1) it is more likely the idea for the meeting is my idea, whereas in example (2) there is more of a chance it is Mary's idea.
Example (1) contains less ambiguity than example (2), but both examples contain a certain amount of ambiguity.