BCS is more of a character study, and doesn't have as many guns and 'splosions as BB did. Some may not enjoy that as much. Some may not find Saul as interesting as Walt.
But even if only purely from a production standpoint, it's objectively better, since the cast, crew, writers and staff are more experienced than they were when BB was made. Some have moved on, but the interns and assistants who started with BB have graduated to fill their shoes. People who now have those three-letter acronyms appended to their names in the credits (representing membership in those guilds and honorary societies) earned them as a result of their work on the show.
To me, if BCS was just going to be a rehash of BB, there would really be no point in making the show. Why do more of the same (save that for the CBS shows and other procedurals, and movie franchises)?
BCS tells us the stories of how Jimmy became Saul, how Mike and Hector became who they are, complemented by new characters like Kim, Chuck, Howard, Nacho, and Lalo (in the short time we've seen him, along with Werner). Even Huell and Francesca.
Fans of the shows probably know that Jesse wasn't the only character who wasn't originally envisioned as a long-term regular. Saul and Mike (due to a scheduling conflict for Odenkirk) were both fleeting characters as well. It was Saul, not Mike who was supposed to be the one who cleaned up Jane's duplex.
I think it's fair to say they did a pretty good job running with those characters, making them integral parts of BB, and spawning another show of their own.
