Generally improvement in picture and sound quality. Wonderful to see that the two boxes (in my house) are now integrated into a seemingly seamless entity allowing recordings to be set up on either box from either the upstairs location or the downstairs location. That also applies nicely to the app as well. YouTube, Netflix, Prime Video and the rest of the apps seem to work well although maybe not quite as smooth with some panning material as the Amazon Fire TV Cube. But certainly the navigation within YouTube is much more responsive.
BUT there are some minor and some less minor issues. The minor issue first and that is the complete removal of all the wireless channels that used to start at 901. However the radio apps (including Sounds) are pretty good although sounds won't allow for recording on a programmable basis. However I do miss the convenience of the radio channels and the blank screen that went with them.
Far more annoying, however is that when fast forwarding through the ads the old TiVo6 would go back 8 seconds when you hit play and I had got pretty good at hitting the resumption of whatever I was watching at the end of the ads. That facility has been removed in the new system. Very annoying. Pressure from the advertising industry? Can't see that it helps their cause if I'm more annoyed than I was before.
One other occasional gremlin that has crept in, and I see I'm not alone in spotting this, is the choice to 'resume playing back' a recording is not always given. I was only about 25 minutes into a 2 hour movie when I needed to do other things. When I came back to the recording I was only given the option to watch from the start. The only time the previous system did this was when you were trying to resume very near the end of a recording.
At first, I also missed the automatic skipping back of the fast-forward on the V6 but I now find the 360 implementation just as good. When I come to (for instance) an ad break I simply use to voice command to "skip forward four minutes". Almost always this takes me to the end of the ad break. If it overshoots I use the left-hand arrow (next to the OK button) to skip back 10 seconds or the right-hand button to skip forward 30 seconds. It's now become second nature.
Personally, I've never experienced the other gremlin you mention. The on-screen thumbnail shows how much of a show has been watched or even if it has been watched entirely.
The things I miss from the V6 are the lack of an All4 app and the option to record "new only". I hope both of these arrive with a future update.
I've solved one of the problems. To resume watching a recording go to Saved and then select Continue Watching. This then show you all the series you have started watching but also the partially watched recordings with an indicator bar to show far you have got. I just need to find the same neat solution to resuming where I've got to in a SKY BOX UHD program or movie. At the moment making a note of the time elapsed and using voice control works just fine.
I've even discovered that the SKY material appears here to although with the one caveat that the point reached doesn't always seem to update, especially if you have actually finished watching the programme or film. It's not always clear to understand the programmer's logic as yet.