It really is pretty much a completely different film to the first, ok the plot is pretty much the same but it's a lot more fleshed out and what were the new characters at the time Flash and Cyborg both become the far more integral in this version of the film. So little of Synders footage actually made the Josstice version, it should be a crime that WB signed off on that version to release
The films not quite 4 hours long either, it's just under. Sky over here fecked up the 7am showing by some old Sarah Jessica Parker film instead but thankfully the film was waiting on their on demand service so I watched it that way and so I didn't start watching until 7:05am and it was finished before 11am
The IMAX aspect ratio wasn't really an issue for me, didn't take too long to get used to it at all. Really looking forward to the physical media 4K release now and watching it again