I remember the metz hammerheads well, they date from a time when AA's couldn't hold as much of a charge and things like nicads were the best we could hope for.
I liked the stability of them, there wasn't IS in those days either...
I generally OC cable or wireless flash these days, but I still have a flash grip which occassionally gets a run out for video.
Canon did do an A-TTL hammerhead which I believe can be used manually with E-TTL cameras, but the speedlite form is just what folks prefer these days.
I have always loved Metz - great quality - and their brackets are very well engineered! I still use their 45 CL-4 with my XSi - and for fill it is gorgeous... I would love to use it with my 5DIII - but Metz hasn't engineered their module to work with the 1DX or the MkIII yet... Come one, Metz, I'm waiting!
5DIII, XSi, A2, 10s (x2), 20-35L, 24-70L II, 28-70L, 70-200L, 70-200L IS II, 85L II, 135L, 40 Pancake, 50 Macro, 100 Macro, 135 Soft-Focus, Crappy EF-S Kit Lens, 430EX II, Metz 45 CL-4, Metz 60 CT-4 (x2), White Lightnings, and lots of other junk...