King of Kings works better as a movie imo. I have seen both several times and while King of Kings has its improbable moments when viewed as a work of fiction it is the more successful movie. Of course for somebody familiar with the scriptures and the life of Jesus it may not be good enough but for me it is.
It is one thing to completely discard the work of a composer but to mess with it and release it in mangled and mutilated form - and without success - is inexcusable
I have found the best movies about Jesus (GSET, Jesus Of Nazareth, POTC) are always the ones that let the basic story speak for itself without silly made-up devices. KOK has a wonderful Rozsa score that manages to avoid copying Ben-Hur but on all other levels, acting, script, direction, and Biblical accuracy it has now become over the years increasingly unwatchable to me. "Ben Hur" I grant is not a modicum of authenticity regarding 1st century Judea, but its fictional story is the front-and-center one and done magnificently that I can overlook that in ways I can not with KOK and its thoroughly shallow acting and script.
I don't find the cameos in GSET distracting with the singular exception of Shelley Winters, whose entire part isn't necessary. As someone who first grew up in the era of the all-star cast spectacle typified by the disaster movies and lengthy TV miniseries (like Jesus of Nazareth, which has a galaxy of big names as thorough as GSET), I don't see how GSET is any worse at it (ironically a lot of lesser names in the cast at the time went on to be big names in 60s-70s TV).
I also don't get the argument that its more of an offense to the composer to keep most of his work and with but one exception do it right (remove the intrusion of Handel at the Act 1 close and the score is just fine overall in the film), as opposed to removing the work entirely and not telling the composer about it until he shows up at the premiere. Of course I'll admit I'm one of those who also thinks that with the singular exception of the Ligeti piece, all the temp tracks in 2001 reflect poor directorial judgment on all levels (which is but one of many reasons why 2001 is for me the kind of film that tries my patience in ways GSET never will).
I would certainly love to see a longer version of GSET since its clear that some of the parts like Angela Lansbury's all but invisible Claudia (Pilate's wife) and Richard Conte's Barabbas were likely longer in the original version. It's too bad we'll never be able to see it thanks to MGM (on this we can all agree).