Let's just say that Josephus, like all ancient historians, documented history differently than modern one such as John Keegan or Rick Atkinson might do today.
I'm inclined to swallow most of what Josephus is serving because his is a contemporary account. However, there are archeological contradictions to what Josephus wrote. I think the story of Masada is credible but legitimately problematic. I'm not willing to disbelieve an original source historian unless a modern revisionist produces tangible evidence to the contrary. The absence of something does not prove it's opposite, as "History of Terror" might claim.
These guys are pretty through, yet their investigations are inconclusive as well.
I can understand why the Romans didn't like these particular Jews. 'Who likes assassins"? Had they been able to get their hands on them it wouldn't have been pretty.
I find it very interesting that the Romans probably build the ramp in 6-7 weeks. It really wasn't much of a big deal for their engineering skills. Still looks incredible though doesn't it?
So, why did it take 2+ years to overcome the defenses? Follow the money. Now that rings true!