Picking a favorite Mavic component is a lot like picking which of your children is your favorite. It's unseemly, when we should be celebrating the unique beauty of all of them. But in the recesses of our minds, we all know there's one we favor just a tiny bit more. Sometimes it's rational, sometimes it's just because.
If you pushed me - and I mean really pushed me, it's possible I might admit a slight bias towards the 640 pedal, which is a little odd given that I never ride quill pedals. It's just one of those irrational loves for an unorthodox design. A design which probably isn't Mavic's at all.
The Mavic 640 is a traditionally shaped quill pedal, with a finish quality that has few rivals - with the innards to match. The more common version was intro'd in the early 80's, though a version was available in the 70's as well. Similar inside, but with a riveted (or maybe domed/hammered on, I don't know) cage.
This generation of 640 has replaceable, hard anodized cages, secured with hex head screws. They varied somewhat over the years, with slight color variations in the anodization color, and slightly different logos. I believe the one labeled 'Made In France' on the same side as the Mavic name is the older one, with the other two cages in the picture above being later.
Inside things get get interesting. After removing the the aluminum dust cap, removing the spindle nut and spindle, the inner roller bearing and a traditional sealed bearing are exposed. Roller bearing on the inside bearing surface, traditional on the outer.
If you think the 640 bears an uncanny resemblance to the Specialites TA pedal, you're not alone. While I can't find definitive proof, I think it's a given that the 640 is at least based on the TA pedal. It's possible that Mavic licensed the design, worked from forgings provided by TA, or had TA do everything - the latter two possibilities all things they're known to have done with other components and manufacturers. By all rights, the TA version is nicer - grease port in the end cap, replaceable flip tabs, curvier cage. A very elegant quill pedal - if you're in to that sort of thing.
Parts explosion for those who find themselves with 640's in need of a rebuild.
Kids, if years from now you're reading this, know that it's totally you (whoever is reading this) that is my secret favorite. I never liked that other kid.