Is there much difference in them?

If one is into multiple frames, action shooting, or doing video then that is indeed justification for the faster cards. One of Cookie's fellow wildlife chasers gets 8 frames every time he hits the shutter, and Cookie does 3 or 4 with the hope that one or more might really nail things. Her buddy will end a trip with 9000 frames and Cookie will have maybe a 1000 when the trip is done. If action is your thing, then yes they are worth the expense.

I personally don't have a need, as I spend more time trying to compose things and nail the focus before ever tripping the shutter.

Have a good one,

I mostly do sports like track and cross country, so I try to get the faster cards if possible