What have you done

This oughta be as lively as wheelies vs three points, or trikes vs tailwheels
I'm game for a little fuel on the fire!
I say it depends, and I have two schools of thought on this.
First is what's your reasoning? If you are trying to kill lift to combat squirelly crosswinds or the likes (or patching up a squirelly landing as TomW suggested) it is a wonderful tool!
OTOH, if you are using it to get in shorter, I'd say it
may be ok. For purely fun short stopping, in most planes, like landing on an unobscured straight long approach to painted lines at your freindly fly in, ya it works. But if you're needing to rely soley on those few extra feet to get into your favorite camping spot, then sooner or later your going to be stuck there because the wind or WX changed enough to gobble up the slight difference it made.
Then I have these reservations, in this order;
1) It depends on the pilot; If you can't hit the flaps and make them do what you want blind folded, this is not for you. If you choose to do this anyways, then sooner or later you will be the guy that raises the gear instead of the flaps, or similar...
2) it depends on the aircraft; in my Thrush at almost 5000#s empty and with awesome brakes, it makes no appreciable difference in stopping distance whatsoever. And while shoving it in reverse is extremely hard on props, it would be a far more effective tool. I still clean it up on the roll though, as this facilitates the next take off, or exiting the aircraft to pee. I will on occasion hit the flaps up while still two feet off the ground, but that's a different technique for a different question.
3) it depends on your mission; If you are landing at a 100' wide mile long strip and are trying to impress someone with how quick you can get the flaps up you are expending needless energy... no one cares... If you are on a tighter strip in an RSTOL equipped Cessna arriving full flapped to a 20kt gusty crosswind, losing the flaps on the touchdown is going to be the smartest thing you've done all flight long.
and one last note, in my not so humble opinion, this maneuver, like any other is only as good as you are proficient in it. If you are continually relying on a flap jump, or flap drop to save your bacon because you underestimated the strip, and that's the only time you practice it, sooner or later you will underestimate that too...
Take care, Rob