For ventilation, I've had both downdraft, overhead, and OTR microwave.

I hated the OTR microwave, and don't ever want one again. Ventilation was horrid, and it seemed someone always wanted to use the microwave while I was cooking.

Downdraft—unlike many, I loved having a cooktop in the island, as I had a very large island with plenty of prep space on either side of the cooktop. As for the downdraft, while it worked much better than an OTR microwave, it also sucked BTUs from my gas cooktop. And when it came to keeping smells/smoke from the rest of the house, well, it sucked. and cleaning the grease trap/filter was awful.

Overhead—now, I have a 48" hood that keeps smells and smoke from getting into the room, including when blasting a wok.

Perfect kitchen for me? Large island with a cooktop with a proper overhead hood. But I'm very happy with what i have now.

When a KD says "this is a Viking" - the follow on question is "have they figured out how to alter the laws of physics?"

That statement from the KD is a snobby one with no basis in fact.

Loved my Thermador cooktop and downdraft on the island in my previous home. A semi-open floor plan will result in cooking smells, but, honestly, that’s why we love to cook. The anticipation of a wonderful meal is a component of cooking for friends and family.

The answer to your question is no. I am also concerned that your KD appears to think highly of Viking. Setting aside his/her rec of the downdraft in the first place, the choice of Viking indicates s/he is out of step, since Viking has had a bad rep for quality with the general public for about 5 years (read reviews online), and for much longer with kitchen professionals. Even the idea of brand snobbery for this particular brand is out of date - far outstripped by Wolf, Miele, Gaggenau, and Thermador.

I would talk frankly with your KD about his/her choice here, or even seek another more current KD if available.

To clarify,

That statement is not from "my" KD. At the picture I posted, click on that or go to more info and to the right (scroll down) you will see questions and answers from the designer of that kitchen...the third question is about the no hood over cooktop.

Friedajune, your comment is helpful because IF we go the island cooktop route, I will look into the brands you mentioned. As a matter f fact, I like Thermador.

The most effective downdraft product I've seen is a Cattura by Best. Pairing this with an induction cooktop requires less power than when you use gas. It's also easier to keep clean and gives your island a smoother appearance. Plus it's more powerful and quicker responding than gas. You could add separate ceiling vents and exhaust blower.

Dan,

Wow! Will look into this. Thank you

Electric stove top (induction or regular) works best with a downdraft. A very short run for the down draft would be preferably too so you can maximize the CFM's. I had one in a house a few houses ago. I think that one was 400CFM. I found it much better than the cheapo fan that I had in a rental house that did vent outside, but probably only 100 CFM. It worked ok though and once in my next home which I remodeled the kitchen and added a still somewhat cheap overhead vent fan (300CFM) than what was in the rental and that one worked much better than the downdraft which had higher CFM. I don't cook much smelly stuff or anything needing a lot of CFM, but an above stove top works best even if a lower CFM than a higher CFM downdraft.