FWIW, I decided to compare the compress size between xz(1) and a very large 7z file, using 'xz -9'. Sizes: * uncompress: 36,495,045,244 * gz: 18,729,830,001

FWIW, I decided to compare the compress size between xz(1) and a very large 7z file, using 'xz -9'. Sizes: * uncompress: 36,495,045,244 * gz: 18,729,830,001 * xz: 16,739,567,484 * 7z: 16,257,755,606 7z ended up being about 480 meg smaller, in a way that was a bit unexpected. I was expecting xz to be slightly smaller. Also, this process took about 15 hours.