I'd note that the entry-level Weber spirit line is made in China and is a relatively recent addition to their lineup so I wouldn't necessarily attribute the Weber reputation to those grills. Maybe they're great, maybe you're just paying for the name.
That Napoleon is a shamelessly obvious attempt to knock off the Genesis series, right down to where they've placed the model name. All in all it looks like a pretty decent buy to me. Basically the savings are attributable to it being manufactured in China instead of the USA and a slight discount on branding (I'd guess you probably pay a 10% markup simply because the thing says Weber - although their product support comes along with that).
About.com is actually a great resource for BBQ reviews, I found during my research. A guy named Derrick Riches writes for them and has reviewed an amazingly wide array of models. His opinion on Napoleon grills is that they're generally pretty good, but that Broil King and Weber provide somewhat better value - if you're buying a Napoleon for $750, you can probably get a better Broil King for the same price (i.e.
http://bbq.about.com/od/gasgrillrevi...apr042507a.htm or the Baron 590). That said I doubt you'd be disappointed given that the reviews suggest the manufacturing quality is quite high.
EDIT: Here's the list of the top 10 BBQ's for under $1000 (though this is USA pricing):
http://bbq.about.com/od/gasgrills/tp/aatp060402.htm