I decided to start recording some videos for another project and figured it was finally time to pick up a GoPro - so the question came up as to which one to get. To cut to the chase - I chose the Hero 7. While the 8 has better image stabilization, there were two things that really turned me off to it.
The first thing was that the 8 does not have a user replaceable lens cover. On the 7 and previous models there was a clear lens cover that the user could replace themselves in the event of a scratch. I mean really, it's an action camera, you are eventually going to drop it or it's going to be involved in a drone crash. From what I've seen on YouTube, GoPro will not even replace it if you send it back for service in the event of a scratch. It's not covered under warranty, so they expect you to buy a new unit.
The other thing, which may be a bit nit-picky on my end, is the rubber device mount on the bottom. In previous models the mount where the GoPro screws into things for mounting was made out of hard plastic. Starting with the Hero 8 it's more of a rubbery substance that looks like it has a little give to it. While you can replace the rubbery part if it breaks, it just seems a bit flimsy to me, especially if I'm depending on it to not have my camera flying off somewhere.
Besides these two things, the pricing on the 7 was really attractive.
For futher info be sure to check out some of the many YouTube comparisons which were done. They are the things that alterted me to the above issues and help me decide on which model to go with.