My Weber Genesis Silver B has given my 5 years of great performance. It goes on when I want it to (had to replace the igniter twice), it's sturdy, and it gets as hot as balls. My only real complaint, and it's a big one, is that the grates are worthless.
I started out with cast iron grates, which came with the grill as part of a special Home Depot deal. Cast iron requires maintenance in the form of seasoning and re-seasoning, and doesn't hold up particularly well when subjected to extreme heat and moisture. Cooking-wise, they performed quite well, though. But after two years I just couldn't be bothered keeping up with the maintenance. Out they went.
I looked for porcelain-enameled cast iron grates, which I had read about, and just didn't come up with anything. Frankly, I don't think they exist. So, I opted for the porcelain-enameled steel (Weber 9860) . These are relatively light-weight, and it didn't take too long for the porcelain coating to go bye-bye. And then, of course, came the rust.
The next choice was the stainless steel grates (Weber 9869). Hey, stainless doesn't rust, right? Wrong. I'm not sure what kind of stainless these are made from (there are over a hundred different grades of stainless steel), but rust arrived within a few months. And, they were light-weight ta boot. Worthless, quite frankly.
Fed up and frustrated, I did another search for grates, figuring someone must make a decent grate. It turns out that Weber makes a stainless steel welded-rod grate (Weber 9930), normally used on the Summit series, but they fit the Genesis. In fact, when you go on the Weber web site, you won't see this grate as an option for your Genesis. Don't let that bother you.
Again, I don't know what kind of stainless they're made of, but they're about 10 pounds each (not to mention 90 dollars each...you have to buy two as they are sold individually). The other grates were about 5 pounds a piece (40 bucks for 2) . Heavy metal is a good thing.
So, after one day, and exactly one hamburger, I'm very happy. Let's see if they hold up. At 90 dollars apiece, I sure hope they will.