I decided to do this since on a certain other form some stupid asshats who don't have a clue keep going on about how the Jarvis barrel is so much better then the EFK. These arrogant gas bags are doing this only because EA decided to go with EFK over Jarvis.
It is amazing too me how those folks get any credit at all for knowing anything at all.
Otherwise for starters the over all feel of the EFK is better. Finish on the barrels where they were turned is much better on the EFK. The Jarvis is very coarse, readily visible and felt turning marks. You can even feel them when you cycle the slide.
The finish of the spring retainer really stands out. If you look at the Jarvis where it meets the slide is very stepped and does not have as smooth a transition as the EFK.
If you look closely the Jarvis barrel steps down after the retainer effectively reducing the with and depth of the channel wall of the retaining clip.
Jarvis also short cut making the retainer. If you look you will see that you can not see the clip on the EFK. EFK creates a channel in the retainer for the clip. Not only does this mimic the factory barrel, gives a cleaner appearance it also keeps the clip from loosening up.
This is very important as guys have learned the hard way that it is easy to tweak the spring clip. With the EFK you have a full channel AND the retainer OVER the top of it holding it in place.
On the Jarvis you see the clip exposed AND in a shallow sides channel creating a failure point.
One more thing. If you look at where the threading ends at the chamber end you will see a nice gap on the EFK and the high shoulder of the barrel. This gives you a nice base to tighten against and not damage your threads. With the Jarvis it's much easier to over tighten your barrel appliance and damage threads.
Another pet peeve of mine is the tread protector. The Jarvis has a crappy roll stamped knurling reminiscent of 1980 shitty Colt slide roll stamping. The EFK thread protector has a nice .075 raised band that is then MACHINE knurled instead of some crappy uneven roll stamp.