I am primarily a Canon user but I liked the feature set of the mirrorless Nikon and bought it instead.  I was not disappointed in my decision.  The image quality, ergonomics, operational speed and features make this a well rounded camera for just about all of my imaging needs.  The viewfinder is particularly impressive, bright and clear.  Since I have a lot of F mount lenses from my film days I bought the kit with the FTZ adapter.  Most lenses work good and I was happy to be able to use my  old 24mm AIS.  I did have trouble with a 28mm D lens which didn’t AF at all.  (Recently bought a 60mm G.  Works flawlessly.)  I am pleased with the Z mount kit lens and it produces some very sharp images.  Battery life is not as bad as I had read but I did buy a second battery for backup.  I just wish they had a Z mount macro lens available.  Overall, highly recommended.

Got the shipment within 1 day from BH after being on the list for 3 months from pre-order. Incredible shipping and service from BH! Having only used the Z6 for about 6 outings, it has been a great experience, true test this weekend with two concerts. The Z6 is really well designed, a familiar Nikon through and through. Im glad to have waited for the Nikon release vs switching to Sony, Fuji, etc for a ML system. Sure the Z6 is not perfect (single card slot, auto focus tracking issues) but it sure hits it out of the park with image quality, low light, ergonomics, etc. I have not tested the video yet and anticipate high marks. Battery life has been impressive, can shoot well over 500-600 images on a single charge. More detailed reviews as I get to know my Zix.

Big, bright electronic viewfinder (great for those who wear glasses)!
Silent shutter (w/o flash), and even the regular shutter is pretty quiet.
Three user settings to recall desired parameters.
Auto white balance seems improved over earlier Nikon DSLRs.
Touch screen makes it easy to change settings or you can use the menus and selector if you wish.
FTZ adapter for Nikon AF-S lenses (with focus motors built in). Hopefully Nikon or 3rd party will release an adapter that has a focus motor built in for the Nikon lenses without focus motors, although you can still use manual focus most of those lenses. The extra stabilization this camera has for the sensor itself appears to improve results with longer lenses like the Nikon AF-S 70-300mm IS.
The small nub allows you to easily move the focus point, or you could also use the larger controller and button. Pressing the nub while in AF-C Auto gives you a focus area that will automatically track the subject around the frame.

Minor gripes: No built-in flash, the older low-cost wireless remote will not work with this model (need to upgrade to the newer one), no 4x5 crop option (only the Z7 has this one), no cover protecting the sensor from dust (TBD if this causes issues over time), and only 1 card slot for the (expensive) XQD cards. FWIW, I have never experienced a card failure while shooting digital cameras from Olympus, Canon, and Nikon since the early 2000s.

Bottom line: There is a lot to like about this mirrorless camera. If you are looking to upgrade to a Nikon full frame camera, I wouldnt hesitate to get this one over one of the Nikon DSLR models, which I suspect will eventually become obsolete by this technology.

Initial review, I have camera for 5 days now: Not inexpensive; great camera and lens combo. Camera made in Japan, well build, feels great, bright viewfinder, amazing shots in low light. Works fine with all older Nikon FX lenses using FTZ adapter; D type lenses - manual focus. Works fine in FX mode with Tokina 11-16 manual focus only, starting at 15mm. My plan is to move to Z lenses in the future, as they become available.

Love the Nikon Z6. Coming from D800 and D750, the Z6 holds up really well and surpassed the two DSLRs in many other areas. Cant be much happier.