Short answer is both are good.
The long answer is it depends on how you drive and how your rig is set up.
Icon has always rocked for Toyota. I'm sure the shock tune is going to be at least close for all their products. I don't know anyone who runs Elca and actually never heard of of them. Looking at their site, even the lower end shocks appear to be built properly. Floating piston is a must and their rebuildable. Their "DC" shocks give a better level of tuning. That scores points in all categories for me.
The question is though, how well will they be tuned to your build.
When it comes to a high end adjustable shock's, you need to know how to properly adjust it otherwise you never get the full benefit. On the high end "non adjustable", if you go too far away from stock "unsprung weight" (tire and suspension) the shock may not be tuned to your set up.
My Tacoma has non adjustable Icons. Its pretty close to stock. The compression/rebound is spot on up to about 60 mph on dirt. The vehicle isnt driven that hard. Non adjustable work well there.
My cruiser needs adjustable shocks. I'm too far away from stock to have a company "Guess" at what will work.
Anything you choose will be better then you have now. Both are good. If you go adjustable, learn how to properly adjust them.