The endless loop dacron and the endless loop Excel are the same as far as I know. In reality there are only 3 choices, as far as I know. The fff, excel, and flemish dacron. The fff is grey and black w/ woven end loops. Flemish dacron is green and black, woven end loops. The Excel is endless loop w/ served end loops. The other choices are for pre 2001 carved tips.
I realize this can be confusing. The fff gives you the fastest speeds, has to "stretch" in, and is the most unforgiving in the event of a dry fire. It is the kiss of death for carved tip limbs. It's disadvantages can be negated by the use of a heavier arrow, like Smokes 474 gr "logs". I prefer the Excel, think it shoots faster than the Flemish dacron that Dnk prefers, but don't know for sure. I seem to recall my poi dropping alot when I tried the Flemish dacron. Will post test results when new chrony gets here. Htoler's poll is somewhat handi-capped by the limited number of Excal users here. I count 5 total, Myself, Dnk, Smoke, Planter, and Htoler. Excuse me if I missed anyone. I do know that the Flemish dacron is the quietest, followed in ascending order by the Excel and the fff. I'm also aware of tests Excal has done where an Emax survived dry fires w/ fff. However, there are numerous posts on other forums of folks that weren't that lucky. Dry fires are alot like IRS audits, generally nothing good happens.