I haven’t written a line of either. I could see using Zig, but there’s no plausible scenario where I’d ever write Mojo. Weird proprietary languages tend to be a career pigeonhole: “you’ve been doing what for the last 5 years?”
Like I always say, most languages start off closed, incubated for some years by a tiny group, before being opened. Mojo is no different, in fact, Modular have given a pretty solid timeline about when they plan to open source the compiler - https://youtu.be/XYzp5rzlXqM?si=nmvghH3KWX6SrDzz&t=1025
Looks like I was wrong about having to pay to use Mojo itself. It's their "MAX" product you have to pay for, at least today. The language currently free-of-charge, although proprietary.