I think Plex is great. It features a nice mix of rounded and sharp edges to not look boring, yet is not too funky to be inconvenient to read. It looks good both

I think Plex is great. It features a nice mix of rounded and sharp edges to not look boring, yet is not too funky to be inconvenient to read. It looks good both on screens and printed with toner. I usually put a \usepackage{plex-otf} in my documents which handles all font variant selection for me.