The Antiquities is a work by Josephus during the time of Jesus. It comprises of twenty books in total. In the first parts, Josephus relates the Tanakh, together with the records he had as a Jewish historian. He said, "I shall accurately describe what is written in our records, in the order of time that belongs to them." This meant that the book contains more than what the Bible has. And indeed, the reader will find forests of information from Josephus. This is the reason why scholars do not take for granted Josephus' works as historian. Furthermore, after relating what was in his records, he also notes what was happening in his time politically, religiously and militarily (up to 66 AD) - an added value to Josephus' work.
There are indeed some visible signs that Josephus' Jewish Antiquities had been altered. Notably, with the account of the siege of the Assyrians to Jerusalem where the Bible mentioned 185,000 of the Assyrians were killed by the angel of God (2 Kings 19:35). Josephus appears to believe the account of Sennacherib (the then king of Assyria) and of the Bible, which made him look very self-contradictory. Sennacherib says that he subjugated Jerusalem, while the Bible says that the Assyrians incurred a heavy toll, enough for them to retreat. Josephus appears to believe both accounts in Antiquities.
Second is the account of Jesus, where he mentions of some miracles of Jesus including the resurrection. As one of the Bible scholars notes (Elgin Hushbeck, Jr.), had this account of Josephus been true, he could have been a Christian. He could have been fanatic of Jesus like St. Paul. But he did not proselytise. Moreover, in the first book, he expressed a doubt on Moses' miraculous splitting of the sea by comparing it with the Sea of Pamphilia 'paving the path' to Alexander. If he can doubt a miracle from his Jewish circle, how much more from the then newly-founded Christian sect?
However, these signs of alterations should not put off anyone looking into the history of Judaism or of its surroundings. These are minor. Besides, the scholar should always verify what is recorded by anyone.
Overall, the contents of the book is very valuable. The Bible scholar will find it forestful of information. The only negative thing I would say that is that the book is written in very small fonts. And with its 900 pages, the reader will have to struggle to read it for a long time.