Your best bet is to go to call a good appliance store that carries GE and ask them to recommend a replacement.

My advice, however, is to get a cooktop without a downdraft and instead install a hood somehow someway if possible. If that's completely impossible, ask the appliance rep which downdraft-cooktops are the most effective

I find that glass, enamel, and stainless steel are all really similar in how much effort it takes to keep them clean. The only material that works better is cast iron. It's not that it accrues less splatter, but it wipes off easier and any small residual amount of fat adds to the natural patina. So, instead of carefully scrubbing, I just need to quickly wipe once.

Other than that, the bit that makes cleaning more difficult is just how irregular the surface turns out to be. A smooth surface is by definition much easier to clean. And if you really care about ease of cleaning, then nothing beats induction. Since the actual cooking surface doesn't heat up, nothing burns in and clean up is much simpler.

If you're looking to replace with like for like (not a separate cooktop and downdraft), then you don't have many options. GE does not have an all-stainless option. KitchenAid and Jenn-Air do have a 30" stainless steel model, but they're near identical - both brands are owned by Whirlpool. The Jenn-Air has brass burners, and 10 more cfm on the blower (310 vs 300), but neither of those things is going to make a functional difference, so I'd recommend the KitchenAid since you'll find it cheaper. I think Frigidaire has an unbranded one, and Kenmore (Sears only) as well, but Jenn-Air originated the one piece downdraft cooktop so JA/KA is likely to be your best bet for that style. But don't expect a whole bunch of difference between any of them, you're looking at a very niche appliance.

Owners seem to like this stainless steel Kitchenaid KCGD500GSS.

There are separate downdraft range hoods which you might be able to pair with a cooktop more to your liking. (Induction cooking is cool.)