EL-Nikkor vs. Componon-S

I have an EL-Nikkor 50/2.8 and 80/5.6 and a Componon-S 150.
I am thinking of getting either an EL-Nikkor 105, or a Componon-S 100 for 6x6 and 6x9.
I am partial to Nikon lens, but was told by my college instructor that the Componon-S is a better lens.
But from my research on the web, it seems that there is very little real difference between the EL-Nikkor and Componon-S lenses.
I would like to get feedback of those with experience with these 2 lines of lenses about any "real differences" between them, or are they even enough that I should just get whichever I can get the best deal on?

I would say there is no real difference to be seen in my oppionion. The differnces are so small. I have used mostly Rodenstock and nikkor lenses. Actually I would say Nikkor is for most sizes a tick, a small tick better. Others will claim differently.
The nikkoer has more blades in the aperture, that certainly can't be bad.

Ctein did a pretty comprehensive test of these lenses in Post Exposure and there is't much practical difference. You can read it here; http://ctein.com/booksmpl.htm

The only time you might notice for modest enlargement is if you get a compoNAR or some other nar suffix with denotes a manufacturers cheaper 4 element economy line.

Not sure how the nikon line denotes the cheaper line but one giveaway is the slower aperture for that particular focal length.

There's bigger difference between particular lens samples than between two good-quality 6 element design 100-105 mm enlarger lens.

I can say that I have the Componon-s 100/5.6 for smaller enlargements of 6x6 and 6x4.5 and it is fantastic!! For larger enlargements I recently purchased a Rodenstock Rodogon APO (Non-N) 80/4 and it is incredibly sharp! For 35mm I use a 50/2.8 Nikkor that is fantastic too! Basically you have to buy and try. Enlarging lenses are strange beasts, some get bad copies of certain lenses, while others report they are great. Once you get a good lens never let go of it.

Thanks guys. That takes some of the confusion between brand out. I'll just see which one I can get for the best price.
Yes I would be looking for the Componon-S version. When I first heard the names of the Schnider lenses I was confused, the names of the 3 lens lines were so similar.

I would suggest you also pay attention to ergonomics and things like whether the lens has readable illuminated f/stops.

If you print colour, lenses from the same manufacturer, and of similar vintage, are more likely to have similar colour rendition.

I don't have the 105 nikkor but I do have the 100/5.6 Componon-s and find it one of my sharpest enlerging lenses (I have a few enlarging lenses). I'm not sure that my APO-Rodagon-N 80/4 is any sharper than the Schneider 100/5.6 Componon-s although I haven't compared them directly. I have several Nikkors, 50/2.8, 63/2.8, a couple of 75/4's and all are extremely sharp so I would expect the longer lenses to be extremely good too. I don't think either will dissapoint.

Although these are tests as taking lenses in a macro setting I think they are quite telling. There's a test of the Nikkor here:
http://coinimaging.com/nikon_el105.html

And a few other enlarging lenses here:
http://coinimaging.com/Lens_tests.html

The 80/5.6 EL Nikkor is rated for full coverage for 6x7 negs,and works well,in my practical experience ,for this format.
For 6x9,you should look for the 105mm.