It's the C that has some plastic parts and differing (but minor) controls but certainly not to be scoffed at, again if in good condition. My 2.8C Xenotar is by far my most clean and best-conditioned Rolleiflex I own. My 3.5E3 Xenotar the "roughest" but a joy to use. And my 2.8E Planar (snagged in a Beijing alley antique shop for $150 back in 1999, it's been through heck) has minor fine scratches on the shooting lens but the slightly more moderate contrast as a result makes it my fav of all for portraits, and with a hood and not shooting into the sun is a match in every way to any of the others. All shoot great images. There's little research to be done other than paying the right price (see link above) and finding one in good condition. For some reason the F's are more in demand and go for more yet the others fantastic shooters.