I have this camera for a year now. Before that, I have had the A7 for a couple of years. As Paulo before me, I am also very happy with the camera. The ergonomics have improved from the A7 predecessor. The IBIS is useful for shooting stationary scenes without having to carry a tripod around. I have been using FF sensor cameras for 10 years now so yes, the FF is one of the reasons why I have purchased this camera. I use 3 Nikkor prime lenses (20mm/2.8, 35mm/1.8, 85mm/1.8 ) in manual mode. But I have recently bought a CommLite adapter to enable AF and EXIF data and I have been rather happy with that.
As I said, I am happy with the camera, no regrets. The high ISO noise is a bit higher compared to higher end cameras such as the A7RMII or the Nikon 810. But nothing which can't be dealt with in post processing.
I shoot landscapes, cityscapes, urban and street with the camera. Having AF makes a difference in street shooting but manual focus is OK in other cases. No sports/action for me.
If you are doubting between a FF sensor and an APS-C one, you should take a look at your photography style and decide how important it is to have a little bit of more control on the DoF of your photos. If most of your pictures are shot using apertures f/5.6 or higher, the difference between APS-C and FF won't be an issue. If, however, you continuously shoot at f/1.4-2.8, the FF would be a slight improvement.
Given the same resolution, the main physical difference between the AFS-C and FF sensors is the pitch of a sensel (a single pixel). All other things being equal, the FF sensor will capture more photons and might provide a bit more dynamic range and less noise. However, all things are not always equal and many other factors play a role in the final results. As I stated before, I think that the latest generation of APS-C sensors are, quality-wise, more or less equivalent to the one in the A7MKII. So that wouldn't be the reason why you should go for the one or the other. HTH.