I prefer Winace. I don't know if it's better then winZIP and winRAR in compressing files but it can create and open so many kinds of archives, including .ace .rar .7zip and .zip
As for compressing, it's good, maybe very good. If you want it just to compress .rmf/.vmf .map and .bsp files then it's the best. It compresses a 10mb .rmf to an approximetly 0.5mb zip.
You can get it in
here. It says that winace is a shareware but I had it for a year already, thats far beyhond the elaluation period.