If everything goes well, you have burnt the engines a little more for the short runway. But thats it, we all know its safe...
But if it doesn't, we all know where we would like to be. On the short runway, eng fails at V1 you don't have extra trust to put on (SOP's allowing of course). On the long one you do, your climb out (all things being equal) on the long one will be easier (less flaps generally mean a greater climb rate and the extra thrust you could put on means that gets even better).
But there is of course a flip side. If the engine fails before V1, you stop, right! So on the short one, things are a little tight but the low V1 combined with a short taxi distance means your brakes are pretty cool prior to V1 and have less work to do. On the long one, you've taxied further, the brakes start a little warmer and the V1 is higher so they have a *load* of work to stop you.
There are always flip sides to the coin - Slopey shoulder time...