I've had all three brands at one time or another. My choice is a close race between a Componon S and an EL Nikkor. I currently have a 300mm Componon S that I really like. However, my 150mm El nikkor still seems tops to my eye. Either would serve you fine.
I once had a Rodenstock Rodagon 150mm. After I got the El Nikkor my prints seemed to have alot more snap. Perhaps the El Nikkor is a better design? Somebody here has to know.
I have 50, 80, and 135mm El-Nikkors. My only experience is with them but I have no complaints. If there is a problem with my prints it is most likely due to the printer, not the enlarger or the lenses.
Many printers recommend a longer focal length than "normal" for printing, and I am one of them. I went from a 135 Raptar to 135 Componar to 135 Componon-S, then settled with a 150mm Componon-S. The Schneider lens is very sharp. I have no Nikkor to compare it with, however. In most cases, "it's the Indian, not the arrow."
I've also had all three in various focal lengths. EL-Nikkors do seem to have more contrast and Componon-S looks a little smoother. I eventually traded my small and medium format enlarging lenses for Apo-Rodagons (50mm and 90mm), which are excellent, though I haven't compared them to Apo-Componons. I use a 135mm Rodagon for 4x5", and it seems to be a pretty decent lens, but I'd be tempted to upgrade to an Apo-Rodagon, preferably 150mm instead of 135mm, if one were to come along at a good price.