I use 7 zip for decompression and it does that job well. Don't have need of it to compress. I use Winzip command line app in my back up batch files but I don't think there is a command line version of 7 zip. Winzip is shareware and it requires a licence eventually. the same is true of Winrar but the evaluation period is longer and it's slightly cheaper if you want to be legal. They all seem to perform adequately.
Tony
