I'd say the only time I saw a direct benefit to the e-fan is after they became more reliable, and, at low speed, idling over trails...the mech fan is turning too slowly, and the efan is blasting away.
I put a "crossing Over ride" switch on mine to make sure the fan was OFF when hitting water...so the metal blades hitting stuff, or the efans' etc, are both eliminated as potential issues. (So I never had a stream or crossing failure...as the blades are not under power)
The shroud issues for efans ARE a big problem...as most are not set up correctly....with some guys using only the top part (The BL's stole the bottoms...etc) and the motor for the fan making a centered dead spot if the motor is too close to the fins, etc.
They really work better if the fan can be set back farther from the radiator so the dead spot is reduced and the shroud is set up to cover the entire radiator and not just a fan sized circle, to draw the air through the fins better, etc.
Without fixing the shroud problems, even if the efan's CFM is technically high enough, too many CFM are going around the radiator instead of through it.
So, for me at least, I only bothered when the mech fan clutches failed and the cost to replace it etc motivated me to just toss it and use the E. If the one on my 2004 craps out, I might do another one, or fix it, depending on mood. The one on the 2001 worked like a charm though.
So, yeah, unless you do a lock out for water and sweat the details on the shroud, it probably is not worth doing...and even then, only if the parts need replacing anyway.
The oil cooler and SC radiator are more along the lines of upgrades that I think would make a lot more sense for most people.
