I upgraded from a Moto G4 to a Moto G6. Here are my thoughts. So far I am a little disappointed, but some may just be getting used to a new design.
Screen Size
I saw the spec of a 5.7 on the Moto G6. It wasn't a huge jump over the G4, but I thought a little extra real estate would be nice. What I found when I took it out of the box was that it was taller, but a bit more narrow. I'm still trying to determine if I like this or not. I was hoping for some more width for when I type in landscape. Now I have less. The taller screen might give me some advantage in reading things portrait.
Phone Seems Slippery
Not sure if it is the glass back on the phone or the shape of the phone, but I often feel like it is slipping out of my hand. I go to thumb type and feel like it is going to come out of my hand. I laid my Moto G4 and Moto G6 on my leg while my wife was driving and the G6 kept sliding away. The G4 stayed on my leg.
SD Card and SIM Card Insertion
The way that you insert a SIM card and SD card has changed and I don't like it.
First off, I was going to take my SIM card out of my Moto G4 to use in the Moto G6. In the past, I have been able to do that easily and if things have gone wrong, I could always put the SIM back in my old phone. My G4 was a micro SIM, I think. I think the G6 is a nano SIM. I had to cut my existing card down to make it fit.
The next problem with the G6 SIM card insert is that you no longer take the back off and slide the card in. Now you have to use a paperclip to shove in a little hole to pop and SIM/SD card holder out of the top of the phone. The holder is flimsy. The process of getting it in and out of the phone is sometimes challenging. I often felt like I was going to break the phone or lose my card into the phone.
You set the SIM and the SD cards on the holder and carefully slide the holder back into the top of the phone.
Finger Print Scanner as a Replacement for the On-Screen Buttons
The Moto G6 let me replace the on-screen navigation buttons with the fingerprint scanner. It frees up screen real estate, but it is taking some getting use to. Push the fingerprint sensor and it closes an app. Swipe right on the fingerprint sensor and brings up the task list of recently used apps. Swipe left and it acts like the back button.
One annoying thing with using it as a replacement is that the G6 vibrates everytime you use the fingerprint scanner. I also something close an app when I am trying to go back.
USB Type C
I have accumulated micro USB cables. I have one at work, one at home, and one in each vehicle. I have to get adapters for them all to use with the Moto G6, since it is USB type C. I knew that going in, so I expected it, but as one considers buying the G6, it is something to keep in mind.