Columbus EL (in contrast to ELOS) is a standard-diameter tubeset with very thin walls, in the 0.4 mm range. The steel itself is similar in strength to modern bike steels like 853 or Columbus Nivachrome. ELOS is the same steel and wall thickness, but larger diameter so it's stiffer.

I have an ELOS frame with oversize tubes but not a EL one, so I don't have any direct experience of what you are thinking of buying. All things being equal (joining quality, frame size, bike tires/wheels) I'd expect an EL frame to ride more flexy than an ELOS frame. But my ELOS is very lively and smooth over the bumps. The EL should be even smoother over bumps. Perhaps like a vintage PX-10 or a frame made of Reynolds 753.

I expect the Cyfac to be very high quality.