Originally Posted by keller
Sure it is noticeable. You get 4 times the shutter speed at f/1.4 than at f/2.8... big difference. Of course you have a tiny DOF... in both respects, quite different from f/2.8.
If you don't want to rent another option is to buy used... if you don't like it you can sell it for near what you paid.
Personally, though, I never rent or buy used. I just buy