.zip vs .tar.gz

[steve harley]

they whom i call J. Todd Slack wrote:
> Hi All,
> 
> I have a bunch of old data that I want to compress up but still keep on 
> my system.
> 
> So .zip vs .tar.gz?
> 
> Which will produce a smaller archive?
> 
> I know that I can pass a -9 to .gzip for max compression. Some of these 
> folders are gigs a piece...Testing this would take a long time for me 
> given the sizes of some items.
> 
> Does anybody have thoughts?
> 
> Is there a finder contextual menu extension where I can say "Compress 
> .tar.gz" just like there is to .compress .zip?

don't know which'll be smaller; On My Command has some 
pre-defined items for .tgz etc. (see "Online archive ..." link); 
or use it to create your own:

<http://www.abracode.com/free/cmworkshop/>