Like a lot of you, I am waiting to hear more about EFMJs before committing them to a carry gun. Maybe they are better than Hydrashoks, maybe not, so I will keep the Hydrashoks for now since they have a known and good track record.
The one thing I do think is very cool about the new rounds is that they offer the potential of an expanding round for those areas or states where hollowpoints are illegal. That is something I think is really cool. I also like the fact that for some older 1911s that won't chamber hollowpoints (and were not designed to), that the EFMJ rounds should feed normally in those guns so that the owners can use ammo that has the potential to expand.
One thing I am concerned about is variation in the reliability of expansion based on environmental factors, most notably temperature. I have no doubt that when warm, such as in summertime carry, the silica filler that allows compression/expansion will allow that to happen readily, but maybe too readily of your gun and ammo have been sitting in a hot car all day long in the Texas sun. I also wonder about extreme cold temperatures. Will the cold cause the silica to harded and not let the round expand as designed? Here I am thinking about those of you who carry in states where you get blizzards.
"If you look through your scope and see your shoe, aim higher."
-- said to me by my 11 year old daughter before going out for hogs 8/13/2011