My old Weber Genesis Silver B died recently.  I'm having trouble deciding between the three burner Spirit at $500 and the new Genesis at $700. I'm not too concerned about the smaller size of the Spirit. The hood seems thinner though. I am concerned about heat retention and stability with the Spirit.

Any thoughts?

I have the spirit and like it. It was a gift and might have just gotten the $300 lowes stainless special had I made the purchase but it is nice. Not huge on the tank cover attachment method as kind of a pita, but it is nice looking and functions well so far. My first Webber.

if you have the $$, I'd get the genesis

When you say it died? Did it explode, because otherwise with barely anywork and only a few dollars you can repair that Genesis Silver B to brand new. I just got one off the side of the road this morning and I'm going to replace everything for less than $150 & have a brand new grill this weekend. Well worth the effort

Genesis , but step up to the SUMMIT if you have the $$

Unless something has changed since we bought ours in 2012, Spirits were made in China, Genesis and up were still made here in the US.  The Spirit we bought is a nice grille, but the quality difference in components and construction between the import and the American grills was very noticeable (though comparing the Spirit to a Stok or Charbroil showed it was superior to those).

Couldn't speak to heat retention.  We've done a little low and slow (for which the side to side burners are definitely better than the currently available front to back) and had little trouble unless the wind was kicking up; then the Spirit struggles to keep a stable temp per the lid and an external probe thermometer.  I don't know if the Genesis would be better.

One nice thing about Weber grills is the availability of parts.  Is replacing stuff on yours not an option or do you just want to get a new one?
I've got a stainless steel Genesis from either Lowe's or Home Depot about 7 years ago and I love it.  Haven't had to replace anything except for the cover since that takes the brunt of all the nasty Ohio weather.

The grill was 15 years old. Its time came.

Genesis and not from the Big Box stores. They use better parts at others, Porcelin flame diverters......etc.

I went Genesis.  It was a tough call. Spirit looks like a hell of a deal. I figured the amortized cost was $20 a year extra.

If you want a new grill that's cool but there is no reason you can't fix the old one up to like new condition for a lot less then the cost of a new one. People restore those older Webers all the time and there is a ton of information out there about it if your interested. Just throwing that out there.

But if you still want a new one, I'd go Genesis. The Spirit line is their bare bones budget line and the Summit line is for those that want to impress their friends, the Genesis line (specifically the x-330 models) give you everything your could need or want, choice of colors or SS without breaking the bank.