You might take a look at the CMMG 308
http://www.gunbroker.com/Auction/Vie...Item=374490952
http://www.cmmginc.com/product_p/38aea9a.htm
Has the Geissele trigger, key mod rail, MB, and SS barrel. For $1800 it's not a bad price.
But back to your OP, I've had all but one (Sig) of the guns listed. I still have the KAC (EMC). I had a ton of problems with the OBR heavy, even after sending it back multiple times. The LMT is a nice gun but feel very front heavy. If you want the opportunity for a switch barrel it's a good pick unless you go with the PredatOBR. Wes Grant (MSTN) got one of the first released and loves it. He'll be getting a 6.5 barrel made for his.
To me the EMC / ECC is the softer shooting gun on the list. The JP feels the same or better.