Product review (4 stars): Swiss Army Knife of Dual Fuel Ranges
We bought this because we were looking for a:

--dual fuel
--built-in downdraft
--with convection oven
--in black

We needed a range we could use in our island.  I know we could have sprung for a separate downdraft unit or an overhead vent, and gone with any number of other drop-in or slide-in ranges, but that option costs almost again as much as the range itself.  Downdraft Jenn Airs are famous for giving you the flexibility of doing your cooking in places you wouldn't otherwise be able to cook.  And this it does.

And while I'm on the subject of flexibility, this Jenn Air is modular (like many other Jenn Air cooktops and ranges).  The down side is that means you can easily spend a few hundred dollars more on additional modules.  Still, we decided to buy them, and we're glad we did.  The range comes standard with a grill, which we really didn't want, because we have mild weather and we grill outside year-round.  But there it was.  So we bought the griddle element that goes over the grill burners, and we have found that to be a real blessing. We do pancakes and french toast and eggs and bacon and panini sandwiches several times a week--and we really don't miss the other two burners all that much.  But if we did need them, we have them too, having also bought them.

The other reason for buying this range was because we didn't want stainless; we were re-doing our kitchen with black appliances.  And the "floating black glass" goes very well with Kenmore or Whirlpool or Kitchen Aid or any number of other glossy-finished appliances.  And our kitchen has a "period" look (pine plank floors, glazed cupboards, etc) and the range isn't fighting for attention.

I know about the plethora of comments criticizing Jenn Airs for being unreliable, for having an underpowered fan, even for having underpowered burners.  I know that the convection oven doesn't have the third element in the rear that would make it a "true convection" oven.  As Pat Paulson used to say: Picky, picky, picky!  But seriously, folks, in the real world, the vast majority of appliances work as advertised and we don't do flaming cherries jubilee on the cook top.  But we do cook two meals every day, and the thing works marvelously.

The gas burners cook like gas burners should.  The high (16,000) BTU front burner gives heat immediately--we rarely have it turned on its highest setting.  The back burner can maintain a low simmer, which is convenient for keeping things warm.

The fan gets the bacon smell out of the kitchen.

Meanwhile, the oven allows you to bake, broil or roast and has both standard and convection modes.  The oven has a rapid pre-heat function that really is rapid.  And we have found the convection oven to be very useful.  We have baked cookies using convection and they came out uniformly brown--but with no time savings.  (You do have the option to bake multiple pans at once, so that would in fact save you time.)  Then we roasted prime rib using both convection mode and the built-in temperature probe, and it worked just as it should.  (We browned the roast on the cooktop in a dutch oven and then roasted it in the same pan at low (200 deg) temperature, and the prime rib was crusted on the outside and moist inside.  Perfect!)

If you want your range in an odd place (like an island), if you want black appliances, and if you are willing to spring for some extras to really put the "mod" into your modular range (buy the griddle--you'll love it!), this range is a solid contender.  We do plenty of cooking at our house, and it works like a champ.  And while it would be nice to have four burners, a griddle and a grill at our disposal in an instant, in practice, we enjoy the two burners and a griddle every day, knowing that the other modules are just a couple minutes away.