Without a doubt, modern C-41 materials will capture a much wider dynamic range than any E-6 material. Optical printing onto easily available and modestly priced RA-4 materials is possible with C-41, but not with E-6 where your only option is the expensive Ilfochrome process. C-41 offers advantages in a hybrid work flow as well, especially in recent years as these films have been tweaked to perform well as source material for a scanner. Once scanned, you are free to manipulate the color space and gamma as you see fit with the image editor of your choice. Naturally, you can do this with E-6 materials, but you have less information in the form of dynamic range.
For projection, you can't beat E-6 materials or Kodachomes. Even well made, dare I say it, digital images projected through a high quality video projector don't look as nice to me.