Metz 45CL-4 TTL VS. Canon 580EX for a 20D

I need to get a new flash for my canon 20D.
Prior to this camera I was using an A-1 with a 533G flash; I really liked the grip type flash.

I thought I was not going to be able to get a grip type with the 20D, but now I see the Metz. I’m still pretty confused after reading other posts here.

Can the Metz Metz 45CL-4 TTL do everything the 580EX can do? Or specifically is it fully compatible and able to operate in a full auto mode?

B&H lists both of these flashes at the same price, but it appears that one has nicads and a charger with it?

Also do I need some kind of module that is not included in these packages?
These are $224 and the 580EX is $379

http://www.bhphotovide​o.com …ghType=category​Navigation

http://www.bhphotovide​o.com …ghType=category​Navigation

Wow, that's a monster of a flash, and I know next to nothing about it. Here's a few thoughts. You'll get side shadow indoors, and it's pretty slow to recharge. It doesn't appear to have the auto zoom head, and it doesn't support ETTL. Also I don't know if the head swivels. Metz do flashes that are similar to the 580EX, but by many reports they're better, auto mode being more consistent than ETTL.

The Metz 45CL is
1. less powerful than 580EX
2. not capable of ETTL, nor providing flash focus
3. recycles very fast, if you use a Quantum Turbo
4. no zoom head, but does tilt
5. has highly reliable and accurate Auto mode
6. requires use of 3000C and 3102 module to work with 20D

The Metz 54MZ does everything that 580EX does (except not compatible with Canon's wireless flash), yet does not require the FEC to be set in order to have a correct exposure, and is less expensive than 580EX

Thanks... guess I'll buy the 580EX