His Leonardo biography is mediocre at best. It may read smoothly but he lacks a good grasp of the subject matter. Instead, Leonardo is like an earlier Steve Jobs of some kind.

IMO, Leonardo biography is an ok exposition to the time period and contains interesting trivia.

Could you recommend a better biography from that period?

I've enjoyed some of Walter Isaacson's books but always worried an internet-intellectual would roast me for that.

I think those biographies are more pop than his fans like to think and more academic than his detractors might imagine.

I don't think there is anything wrong in 'pop' when the work is intended to be popular. I expect the biographer to verify her sources but as a reader I'm not going to go out (generally) to verify them.

Things that happened, happened. Most of all when reading popular biographies I want to be introduced to real things that happened, and if some of that draws my interest, I can then dig in to more academic sources.

The popular biographies offer the '100 feet' view over their subject and the society in which they lived in, and should not be disparaged if they succeed in doing that in a readable and entertaining manner.

Yeah, I just think 'pop' is a good word to take down something seen as a comprehensive work when it's more of a '100 foot overview.'

That's a rare thing, though. The adjective should probably be used neutrally way more often than derogatorily.

Is his Einstein biography any better?

I enjoyed all of historical Isaacson biographies (Einstein, Leonardo, Jobs, Franklin and Innovators).

I suppose the the biographies would need a more detailed critique of what people did not like in them to say anything particular about one of them.

Jobs biography alone does not give a sufficient image of the man, for example. But when combined with "Becoming Steve Jobs" the picture is more well rounded. That does not mean I did not enjoy the book.