Which fan

If they both fit your shroud, and you already own them both; I think I would use the smallest one that gets the job done.
If your 360 is stockish, I would try the one on the right.
If cammed and high-compression, or if towing;then the left; that sucker moves some air alrightie..

Check for cracks around the mounting points.

I'm guessing the cut tip is for balancing. The left one has one or maybe two different sized blades to accomplish the same thing, and I guess, to reduce roar; I've never really thought about it..