Best Vacuum 2025 Calendar – So, it is the best ever means it's the best of all time, up to the present. In your context, the best relates to {something}, whereas best relates to a course of action. Which one is the best is obviously a question format, so it makes sense that which one the best is should be the correct form. it was the best ever means either it was the best up to that.

Best Vacuum 2025 Calendar

The word best is an adjective, and adjectives do not take articles by themselves. Which one is the best is obviously a question format, so it makes sense that which one the best is should be the correct form.