Bobiverse has lots of _good_ physics, especially around astromechanics, but also lots of questionable, bad, and unexplained physics. Specifically the FTL communications and the clone personality differences exist entirely for plot reasons, have very little explanation, and cause significant amounts of disbelief that must be suspended.
Sure, but I find most interesting science fiction takes liberty at least somewhere. I'm willing to let the author play a little loosely with a few things, which are hopefully explained as "additional input we don't quite understand alter known theories" instead of "ignore this well accepted thing", if it adds significantly to the story.
FTL communication? Eh, there's both enough new stuff to discover in physics and it provides such a massive boost to most stories that I'm generally willing to allow it, if treated well.
The clone personalities diverging almost immediately? Kinda torn. On the one hand, I think they would diverge significantly eventually anyway (take anyone at age 40 and give them a couple hundred years of experience being a martial protector, trying to unite nations, an R&D head, or a explorer of the wondrous, and you're bound to come out the other side with large differences), so I'm not sure how important it was to have it immediately if the plot points it helped could have been achieved in some other manner.
I rather like the explanation for the lack of FTL travel/communication around here in Vernor Vinge's Zones of Thought books (first two are some of the best SF novels ever written, third one is pretty awful).
Edit: Added "around here" - which is quite important.... ;-)
The engines also seem to be perpetual motion machines of some sort or at least pull massive amounts of energy out of nowhere. The fact they can do that at absurd scales becomes a large plot point so it's kind of hard to ignore.
I thought the original generators were fusion and powered some kind of ion engines?
The ostensible explanation for the later casimir generators was that they were pulling energy from vacuum fluctuations in a similar way that armature-linked buoys can generate power from ocean waves, but they were pretty vague on how that could provide more than a minuscule amount of power. Instead it was portrayed as being able to supply orders of magnitude more energy than fusion, which seems implausible. But at that point we're like 2 books in and already pretty invested...
the power on self test includes a check to determine if he’s a copy. failing that check is so traumatic the only coping mechanism is to create a new identity. each new identity extends some prototype that was known to bob prime. it’s like how smashing the same cup again and again would break in similar but different ways.
