I remember once for a project I needed to squeeze a bunch of data onto about 4 DVDs. It was a variety of media. Text, gifs, jpgs, avis, mpegs, wavs, mp3s, isos.
Basically all kinds of media. Basic compression got me within about 100MB of fitting on the last DVD, so I needed to squeeze it just a BIT more.
So I decided to make it a contest. What would compress a bunch of random shit better, 7Zip or WinRar?
Well, it turns out it was WinRar, by a landslide.
Not only that, but 7zip was REALLY FUCKING SLOW, took up a SHITLOAD of RAM and on some files, INCREASED their filesize. Basically worthless. The only reason people use it is because they are somehow guilted by a purchase prompt on WinRar or think all open source shit is immediately better than all alternatives.
7zip sucks donkey balls, get used to it. (And WinRar HANDLES 7zip files)