I had no idea that Doyle, in his years since B5 went off the air, came out as a conservative (!), ran for US Congress (!!), and now has a successful radio talk show (!!!). His prose is articulate and well sourced, but he suffers from the hyperbolic tendencies of many folks in politics: he calls his opponents names without regard to the fact that it will make his arguments be taken less seriously. His arguments are actually pretty good - I didn't learn a whole lot of new things from the book (largely because I'm already plugged into some of the not-so-nutty conservative blogosphere, and read National Review). My favorite portion was his anecdotes from growing up: he comes across like a "fake it till you make it" sort of lovable rogue.
One weakness in Doyle's arguments is that he sometimes lumps weaker ones in with stronger ones - as an example, in a section lambasting various members of Congress for their self-servingly spineless behavior, he includes a swipe at Rep. Shelley Berkeley for her failure to make a vote authorizing funding for the Katrina recovery efforts. Berkeley's offense comes across as trivial when compared to some of the others listed (Rangel, Reid, Jefferson, Stevens, etc), and it makes him sound like either a hardcore partisan or someone with a perpetual grievance. However, a redeeming element of Doyle's approach is his actual lack of partisan behavior - not that he doesn't take sides, but rather he does not excuse any anti-conservative behavior on the part of Republicans. Doyle doesn't seem to have the attitude "he's a rascal, but he's our rascal," and I see that as a plus.
This is pretty much a tea-party red-meat book, but it's pretty well written, and the anecdotal sections are great. I'm not sure that this would be the book I would recommend to your garden-variety liberal to give them a better appreciation of the conservative mindset - the name-calling is off-putting, and I think that it weakens the whole.