Really not worth it as most only see about 5 degree lower load temp and you have to shave down the mobo's CPU bracket to compensate for the IHS being removed. Otherwise the heatsink will not make good contact with the die. If you mess up at all during removal your CPU is most likely dead as the die will be crushed or otherwise damaged. Removing the IHS is a new thing going around the OC crowd.
I pissed and moaned for 5 years over the stupidity of unpackaged die on $1000 CPUs. Now that they got smart and put them under metal again people actually want to take the covers off for a few degress of cooling?
It's not a bad idea. The decrease in temps are nice for the overclocking community because a 5 degree decrease can mean a little more speed. Now whether that performance is entirely worth it is a different thing, but to overclockers it is completely worth it.