They are the same. Both part of the whirlpool family of brands. The burners differ slightly but the downdraft mechanism is the same. Go with whichever you like better, they are both decent cooktops.

A better option would be to replace with a non-ventilated radiant or induction cooktop, and go with a separate telescopic downdraft behind.

Yes, it will cost more, and be more difficult to retrofit, but when it's all done you'll be much happier, especially if you go with an induction cooktop.

Same/same anemic performance. Go with an overhead hood instead. It actually works with the laws of physics instead of trying to work against them.

In my experience telescoping downdrafts are significantly more effective than the traditional JennAir kind. At least you're trying to pull the air to the side instead of straight down and fighting the laws of physics a bit less. The best downdrafts are those Gaggenau Vario swivel ones but I'm not even sure if they make those anymore, and they are/were super pricy.

I would assume that if an affordable overhead hood install was feasible, OP would not have started a thread about replacement downdraft cooktops. But guess I could always be wrong.