I think that, when considering other opinions on cars, it is important to differentiate between those who know either through direct experience or indirect experience (i.e. a partner of somebody who owns one or a family member etc.) and those who simply regurgitate the opinions of other people who are supposedly knowledgeable.
I know many people who have slated car x without any personal information whatsoever and were doing so simply to appear knowledgeable in front of their friends and family.
Others opinions are of course important in the decision making process, but they are just that, opinions. I don't choose what albums I buy simply because someone else says it's great, I make that decision myself, though in cases where I know my music tastes have been similar to somebody else's in the past, I sometimes take a punt on their advice.
Personally I quite like things like the ReliabilityIndex (
http://www.reliabilityindex.com/) there are others out there, while not entirely impartial, they do offer a data based outlook at the reliability aspects of a car, rather than Dave down the pub saying they're rubbish because his mate Darren doesn't like them as Darren's boss once owned one and it went wrong.
This wasn't a snipe at anybody in this thread per se, nor was it an attempt to specifically defend the Megane, from my own research I can tell you that the trim and general build quality of the early to mid Mk2's IS worse than many other rivals (with an apparant noted increase from late 06 plate onwards when the final facelift of the Mk2 happened), however I can also say that if they work as they were designed to (and many do day in day out), they CAN be a fantastic bargain.