The coffin smoother on the left is from Steve Voigt. It is a wonderful plane and the most used of this group. Next to it is an older ECE coffin with a double iron, also a very good smoother. Next is a ECE single iron "Gent's" plane which is a great plane if the wood is well behaved. And the last is a newer ECE listed as a Jack plane, as best I can tell the only difference between it and their smoother is the grind of the iron. It works well and is cheap, a real bargain if you are looking for a smoother/jack plane.
The woodies smoothers get about the same utilization as the metal smoothers. There really is no rhyme or reason one is picked up over the other. They all do the job and are are a pleasure to use, pick one.