I started to think about this comparison after hearing someone say “meet up with” a couple of days ago.

Problem:
Only two of these three are proper English.

Explanation:
I recently heard someone on the radio say “I was going to meet up with Chris in Galveston.”

This sentence contains an unnecessary preposition. The expression “meet up with” means exactly what “meet with” means but contains the unnecessary preposition “up” and therefore is not proper English.

In contrast, “meet with” is proper English but does not mean what “meet” means.

• If I “meet John”, then he and I interact with one another for the first time.
• If I “meet with John”, then he and I already know one another and are having another meeting together.

Solution:
Use “meet” for an initial, introductory meeting between two parties. Use “meet with” for subsequent meetings between two parties. Avoid “meet up with”.