The Elinchroms both set-up and rear down much easier than the Profoto for location work ... but the Profoto is small and can be left set-up for transport IF you have a SUV or a hatch-back.
The 27.5 inch Rotolux Deep Octa is very manageable and easy to set-up ... the 39" is a bit harder. Both have proprietary Elinchrom speed-rings that allow their quick-snap-in-rib convenience, so to use either version on a Profoto head you need the EL to Profoto adapter:
Elinchrom Profoto Head to Elinchrom Acc. Adapter EL 26333 B&H
Be aware that his EL adapter eliminates the ability to slide the modifier along the body of the Profoto strobe to alter the light throw like you can with the Profoto mount modifiers. The other small advantage of the Profoto mods is that the speed-ring can be changed to work on any strobe head.
I have the Profoto 600B AIR Lith box and Acute B head. The 27.5" Deep Octa works well on this head, but the 39" gets a bit heavy hanging out on the end of that small B head ... (rant)
IMO, the Elinchrom mount is one of the worst I've ever used and sucks compared to the Profoto mount when it comes to a securely fastening larger modifiers. The 39" is probably okay on a good light stand, but if you want to use the Acute B on a hand-held light pole (mobile boom arm), I'd recommend the 27.5" Deep Octa. This is how I primarily use the Profoto 600 box ... as a mobile light held by an assistant. So, it depends on your intended use.
Frankly, IF I get the 39" with EL adapter (my buddy has one for his 600B, so I've seen it in action), I'd epoxy the EL/Profoto adapter to the Deep Octa's speed-ring.
Were I you, I'd order both Elinchroms and the EL adapter and try both for set-up and mounting and then send one back.
My 2¢
-Marc