I'd have to support those people who think the Masters of Rome series is good. Personally, I found them a great read! In fact, they're the reason I became interested in Roman history. I'd never read anything about Rome before, found The Grass Crown in a second-hand bookshop, bought it, and was instantly hooked. I *HAD* to read more!
I agree with primuspilus' comment, though, that the later books aren't as good as the earlier ones. I actually think they became a little more soap-opera-y. But, still, she did a good job. And, as I've started reading more classical sources, as well as "official histories", I realise that she did a good job "bringing history to life".
However, she does seem to bend over backwards to demonstrate that Caesar was merely a good person (who happened to be a genius!) who was wronged by the Senate and had to do what he did to clear his name, while everything else I've read tries to show him as someone who wanted to be a tyrant from day one.
Hmmm???