Here are some distinctions I found online:
Classics are timeless mowers with an agreeable standard of excellence. Although, "agreeable" is not always the case, and sometimes this definition is more subjective than not.
Collectibles contain rare features or low numbers of production.
Antique is over 100 years old and look it.
Vintage is aged, but is coming back in popularity. Vintage is often used loosely and should also state the production year for clarity.
What do you guys think?
