Performance is ok, (when run in my game, I have done no real testing yet) compared with the standard jME DepthOfFieldFilter :
at lowest samples, 1, it runs a bit slower, but there is no effect so its useless
at decenty quality (18 samples) it runs about 23% slower
at great quality (196 samples) it runs 50% slower.
there is no limit to the quality setting but above 196 there is little visual difference.
It’s still really early on but it looks like it will be much slower than the normal DOF filter, but may be useful for projects targetting good hardware.