I've also started on Darth Plagueis and thus far am loving it. (I did spent the first few chapters eagerly awaiting Palpatine's appearance. What can I say, as a character he's a very effective complete monster, even more so in this book.) Some very intriguing looks into both Sith philosophy and galactic politics and great characterizations make this a worthy addition to the star wars universe. (And I'm not even half way through yet...)
In part due to the discussion you and I had during our last meet, I went and got it, too.

I enjoyed it, though I was amused to find that the one thing that put me off was the same thing I applaud when I encounter it in Trek novels - the continuity references. I got the impression that the novel was stringing together a lot of other plots and stories as a backdrop to its own, and I wasn't really familiar with many. It wasn't too much of a problem - the plot could be followed just fine so long as you know the films - but I think I would've found it a lot more meaningful had I understood the significance of all the references. As I say, it was amusing to feel what those Trek lit fans less committed than I might feel when reading a KRAD novel, for instance. The sense that you're missing out on a chunk of knowledge that isn't necessary but would enhance your enjoyment.
One thing I noticed intrigued me, though I think I'm probably wrong and this is another Lord Odo, so to speak (older references that have nothing to do with popular sci-fi that make us sci-fi fans think they might). Parts of Darth Plagueis' philosophy reminded me very strongly of the Shadows from
Babylon Five (as a big B5 fan, such links come easily, though in this case very appropriate in places). Then I got to a speech of his where, in describing his plans and philosophies, he mentioned how his chaotic plans' sucess would be measured in "signs and portents". Okay, I know that's a biblical quote (though it seems the translation "signs and symbols" or "signs and wonders" is preferred, given my admittedly short internet search), and there were other bible references in the novel, particularly in the scene when Palpatine makes Palpatine pulp (long story), but given the philosophical context, and with my mind already having made Shadow connections, it gave me a bit of a jolt. Was that perhaps intended to reference the B5 episode that introduces the Shadows to the setting (which itself presumably draws inspiration from the Biblical quote)? Or is it
just drawing on the same source, without the additional nod? I can clearly see why Isaiah 8 is relevant to Plagueis, but if the favoured translation is "symbols" or "wonders", as it seemed to be by far (only one of the listed variants used "portents"), then why use "portents"? Is this a bonus of sorts for sci-fi fans?