Regarding the .alz format

.alz format was an archiving format that is favored by a lot of people in the Korean internet community - where ESTsoft and Alzip is from.
I dont like alz format either - its compression rate is superior but it just isnt compatible with other softwares and heck, sometimes even with alzip itself. ESTsoft tends to advocate the alz format but I think you should be safer sticking to rar or zip. :)

jobush about ALZip