Ich bin heut auch in einem Nachbarforum darauf gestoßen:
If You are searching for speed, try to avoid Tomioka 55/1.4 (Rikenon, Revuenon, Cosinon, Chinon, Porst etc.) as it's transmission factor is not very impressive.
I've replaced my Cosinon 55/1.4 with mentioned SMC 50/1.4 and now I've really fast lens.

Maybe your copy is faulty or something. I have both Revuenon and Porst and they are excellent.

I do not say, that it is BAD lens.
I have some excellent quality shots from Cosinon 55/1.4, and all I can say is "it is very good lens overall".
But I've tested my Cosinon 55/1.4 (and some time later my friend's Revuenon 55/1.4 as well) against my 58/2 Helios 44-2, and my EOS indicated that all three lenses set to full aperture transmits the same amount of light - so my Helios 58/2 set to f2 is as fast as Cosinon 55/1.4 set to f1.4. It was quite odd for me at first, I though that it's something wrong with my camera - so I've used my old Praktica as well, with similar result.
My old Helios decided to behave as slower than f1.4 with Pentax SMC 50/1.4,
that's all.
So I can recommend these 55/1.4 lenses for shallow DOF, but it is quite obvious to me that lens aperture does not always compete with light transmission factor when You compare two different lenses.
Of course, as Voytek says, I can be wrong and some of these "generic" 55/1.4 lenses are not so generic and differs in optical construction and the quality of the coating (which can be the main factor of better/worse light transmission factor).
So correcting myself - I've tested two 55/1.4 lenses (Cosinon and Revuenon) and although both were more than OK in case of image quality - these two lenses were not impressive in case of light transmission factor.

I think, that iIt would be nice to have lenses with dual aperture scale -f-stops and T-stops.
In the spare time I've tested some of my lenses to find that i.e. my Orestegor 200/4 is as fast as my Telear 200/3.5, and my friend's "noname" 200/4 telephoto shall have 200/5.6 on it's name ring, when the lens "speed" is what we need.
http://en.wikipedia.org/wiki/F-number#T-stops