Note that Thom has a dedicated site for the Nikon Z System: zsystemuser.com
Nikon's Z series of full frame cameras was introduced in 2018, and consists of full frame 24mp and 45mp full frame (FX) options, much like the D780 and D850 DSLR options, as well as a 20mp APS-C (DX) option that slots between a D5xxx and D7xxx.
So What Would Thom Get? Any of the Z cameras are solid choices, so it depends a bit on what you want and need. The Z50 is the smallest, most travel-worthy camera of the bunch, but none are slouches in that regard. The Z5, Z6, Z6 II, Z7, and Z7 II, because of the full frame sensor in them, just tend to be a bit bigger and heavier. Videographers should get a Z6 or Z6 II. Still photographers looking for the best bargain should get the Z5. Most of the rest should consider the Z7 or Z7 II.