@Cobalt I haven't used it for zines, but the print files for my #glitchbook covers and the dot-grid inside pages were made with Scribus.
It is ... weird in parts but very mighty once you get used to it.
@Cobalt
I did layout for one issue of our zine in scribus and it worked well.
It was kind of too much for me, though. I got lots of contributions in RTF and (unfortunately) docx formats, so I ended up switching to libreoffice to do my layout at 5.5x8.5, and then depending on my printer's built in booklet option for final formating.