I find winrar a much better product than Winzip, mainly because it's faster and has really nice shell integrations. Plus it can compress to more than winzip can. Finally my unofficial tests show that it produces smaller file sizes (on max compression) than winzip, and does it faster too. Unlike winzip it's really fast and compact, plus you can skin it

Plus don't forget Winzip encryption is easily crackable.
Yes it's biased, but --
http://www.rarsoft.com/compare.htm