I don't normally write amazon reviews so this is partly just to counteract the incredibly misleading one-star review that is already there. That review, although clearly by a raving Euro-sceptic (as his/her reference to the Irish vote shows) may be giving out the wrong idea. This book is an excellent analysis of the Eu's democratic/legitimacy deficit and addresses the fundemental problem that while the EU is procedurally very democratic (elected Council, elected Parliament, indirectly elected Commission), moreso than the UK, it lacks a 'European public' necessary to make these institutions work properly. He does not say that the system is perfect (far from it, hence the title 'what's wrong with the EU) and does not think the US system is perfect, just the only system that we can reasonably compare the EU to (although the EU is unique and thus comparisons don't work).
If Hix is pushing any agenda at all, it is to stop the EU being run by 'faceless Brussels bureaucrats', something surely everyone wants?!
This is an excellent book and as someone who did their Masters degree partly on European Union politics I found it incredibly useful both for the points it makes and the style used to make them which is eloquent and accessible.