Nice to hear that Mojave feels a bit smoother than High Sierra. I'm getting bits of lag and dropped frames in High Sierra on a 15" retina 2012. Things like switching Safari tabs or Spaces, there's a noticeable delay or jerkiness to the animations. Are other retina 2012 15" users experiencing this on High Sierra as well, or just me? I've just gotten this machine so I haven't grown with it. I've been using a 2016 15" which is buttery smooth so the difference is very noticeable. Both machines are on 10.13.5. I used Migration Assistant from the 2016 to the 2012 so maybe that brought over something the 2012 doesn't like? Is it worth restoring the 2012 and setting it all up manually or is the jerkiness just par for the course on that machine and I should just live with it until Mojave is out?
I had to downgrade from HS to Sierra after a few days with HS experiencing some UI lags, it was very frustrating to wait a second for comon task you do a lot of times a day. Downgrading was a pain and corrupted some modified dates of folders but it was super worth.
I'm afraid of upgrading now my rMBP 2012 to any OS beyond Sierra.
by the way, I used a cleqn instalation with manual install of apps, so dont blame the migration process