I recently tried Metz 58 AF-1 flash. Overall impression is very positive.
I think what makes the flash to stand out is attention to details (at least in comparison with Canon units).
Little things like low battery indicator or beep function make you wonder why don't all flashes have that

My observations in detail are here: Metz 58 review

Interesting review, thanks. I have one of these units and like the quick recharge and power. It also seems capable of a lot of exposures on a good set of rechargeable batteries. One problem I have is that coverage can sometimes be a little uneven, particularly low in the field of view. This is inconsistent and easily overcome using the extended zoom function. I just wondered if you found the coverage to be better? Otherwise a great flashgun.

Don.

Can it fire or be fired by other canon strobes like the 580? Could it be used in a group mixed with them. What is the advantage to using this over a 580?

Metz manuals in english are here: http://www.metz.de/en/photo-electronics/in.../mecablitz.html

Metz 58 AF-1 can control (or be controlled by) other Canon units. Make sure you get the "C" version that is designed for Canon cameras.
Advantages over 580? Well, it's not exactly better or worse. There is a number of differences. I'll try to post an article on that in the near future.

Hi Don,
I haven't noticed any inconsistency in teh real life shots. I'll be doing controlled frame coverage test soon and will post the results (similar to my Speedlite 580EX II test).

Haven't gotten to the frame coverage test yet, but just finished testing the wink light, extended zoom and the catchlight.
It was rather interesting to compare pictures side-by-side. I've selected 15 images to show the differences in lighting: Metz 58 test

Here is, for example, how close the wink light and cathchlight card can come (ceiling bounce):


The catchlight card can go lighter (shadow wise) then this, but the wink light cannot. The image above (right) was taken at the minimum wink light power from 6 feet.

And the extended zoom... I don't really find it to be useful.

Another Mecablitz 58 AF-1 test - frame coverage, white card light coverage, vertical head position...