As a daily user of YellowMug's great EasyCrop app (a massive timesaver!), I'm delighted to have the chance to rave about YemuZip.
Recently I had to zip over 80 humongous files (between 1GB and 2GB). OS X's built-in zip compression utility is good, but it's slow and it eats system memory. If you have a lot of really big files to zip, you'll end up with lots of inactive memory (as revealed by Activity Monitor).
So, I fired up the free version of YemuZip, which I've used with good results in the past. It did such a superb job that I bought the paid version of YemuZip on purpose...just for the pure selfish pleasure of giving YellowMug my $upport.
Oh...and I should mention that YemuZip is very conservative in the amount of system memory it renders inactive after compressing a bunch of files. Thanks, YellowMug, for writing great apps!