I got myself some short fins since as a fairly weak swimmer especially in my legs I wanted a bit more confidence and power when swimming in the sea.
However one basic problem I've encountered - how to get out through the breaking waves with them on my feet?! With moderate waves (not dangerous to play in) they are breaking in quite shallow water, and I am so clumsy in my fins that even in knee-depth water or so I get knocked over... but the water is too shallow to swim in. On a fairly flat beach I have to go out a long way to reach deeper water, I can't just dive into a wave and swim out.
I tried to put the fins on once I've swum out, but they have straps (since they don't float) so this is not really possible it seems.