Yah, they are great grills and a good value in the $600 - $1000 and up range. They pretty much dominate that price range. But, if you want the same grilling performance at less than half the cost, find a used Genesis Silver B or Genesis 1000 to clean up and fix up and you can do that for less than half of a new Genesis. Many hardcore grillers prefer the older Genesis grills because they have the E-W oriented burners instead of the N-S burners in the new grills. If you plan to use a rotisserie, don't even consider the N-S burner grills.
The other great thing about Weber grills, both new and old, is that there is a lot of parts available for them. While the older Webers are probably more durable than the newer ones, it is still easy to find parts for them. They are not "throw away" grills, like many of the other brands in the $100 - $400 range where you use them two or three years and then dump them and buy a new one. The webers last a long time as is, but when they do need new parts, you can find them easily.
If you have the $650 to spend, then yah, grab a new Genesis II, but if you want to have a great grill and $300 worth of extra gear, Ribeyes, Ribs, Roasts and chickens, then find a used Genesis Silver B or Genesis 1000 for sale for about $50, put some time in cleaning it up, fix the few things than need fixing or replacing and you will have a great grilling machine that will last you for a couple decades if you take care of it. Then hit the butcher shop and stock up the freezer and buy a rotisserie and a remote thermometer and take the wife out to the movies on what you saved.
I bought my 25 year old Genesis 1000 last summer for $20, put about $100 into it it is a great grilling machine.