What's the current state of check printing in Quicken Mac?

Check printing hasn't changed in Quicken Mac in many years. The only tweak the developers have made since modern Quicken Mac came out more than a decade ago is an option to switch from regular to bold font, because people complained the printing was too light to read. But you can't choose a font, choose a size, and perhaps most importantly, can't adjust the spacing of individual elements within a check. (The issue with spacing is that the Memo line prints either too high or too low, because you can only move all the text up or down as one unit.) That said, it does print checks and should be serviceable for people in your situation.

I don't print checks in Quicken, as I pay most bills online and average less than a dozen checks a year. But from reading user comments over the years, I would recommend the 1-per-page voucher checks instead of the 3-checks per page. The latter can create struggles with your printer feeder, whereas the former should work pretty straightforwardly.

I will leave it to others to recommend specific check vendors they like. In my work environment, I have liked CheckDepot.com for good quality, accurate and prompt service, and good prices. But I haven't priced out checks anytime recently.