I think the Magician has an interesting turn of events, where there's some actual good character development.
Interesting and entertaining parts were Josh and his awakening, the appearance of Mars, who turns out to be Ares, who is the Babylonian Nergal, and actually turns out to be the Aztec deity called 'Huitzilopochtli'.
There's even a little bit of quarrel between the twins too, about Flamel's intentions, which is an improvement from the earlier novel.
However, a bit of extra humour would be appreciated, as it was quite dull regarding actual jokes.
Therefore, I would give it a 4/5.