I don't know if there's a nice way to say this, so I'll just put it out there for y'all:
ZIP is the One True File Compression Format. Everything else lost.
ZIP files win for two reasons:
ZIP is integrated into every OS currently in production
ZIP files are good enough
Once upon a time, disk drives were never big enough. There was never enough memory in the machine to have filesystems with seemingly unlimited files allowed. We communicated over modems on POTS lines that were slow, if they worked well at all. We spent a lot of time on error correction technologies, and file compression schemes. Compression meant you could do that backup onto 6 floppies, instead of 10. It meant you could download that shareware overnight, instead of over two days. It was important, and we all geeked out appropriately over every new format that would compress files smaller than the one we were using now.
There was quite the list of compression formats that came out over the years as the state of the art advanced. Each better than the ones before it in some way. Off the top of my head, I remember LHA, LZH, ARJ, bzip2, RAR, 7zip, and on the Mac side we had SIT and CPT. There are tons more. The Wikipedia List of Archive Formats is like a walk down memory lane.
But I no longer care about the best compression. The internet is fast, and disk space is cheap. I don't care that your format of choice will compress a file 2%, or 7%, or even 15% smaller than ZIP will. I don't care that your log files are 150K in size when instead it they could be shrunk to 100K, I just care that they don't take up 250 Megabytes on the FTP server and in the support systems.
I also care that it is possible for me to uncompress your log files so I can analyze them for you. I've had enough RAR and 7z files sent my way that I can handle them. But I still groan and roll my eyes a little ever time I see one.