I have used a C's, Nashman and the SS shifter.
-C's I ran in may car for a year, it shifts nice and smooth and easy shifts, it is also isolated so you dont get any vibrations on the shifter. It is the stock height, so some might not like that. I also kept missing third gear while racing and shifting hard/ fast, which is why i pulled it out ans run a shortened stock shifter.
- SS V3 shifter, is super nice and shifts great, I never tried racing or shifting hard but I was really impressed with it for regular driving.
-Nashman, I drove some cars with the early prototype version, and the throw is really, really short, and it is ultra notchy. I personally didnt like it much but others love it, and I have no idea if the new production version is smoother, or if this particular car had stacked shifter bushings to make it so notchy.
- SOGI mod/ shotened stock. I run this currently in my car, I never miss gears while racing, the height is right where I want it, but I also get vibrations through the shifter. I am fine with this one.