There is a downdraft directly behind the cooktop which retracts flush with countertop when not on.

Are your clients happy with its performance?

Yes, they are happy with the downdraft but they knew what to expect as they had one in their previous kitchen. Downdrafts will not capture as much smell/smoke/vapor as a hood fan but the obvious advantage (in a situation like this) is having no visual obstruction.

re downdraft - does one have to have a hood/downdraft when the cooktop faces outward?

You can still use a traditional overhead hood fan as long as it isn't too visually obstructive for you.

whats the barnd of the cooktop and the popup draft used here?