Virtually the same cooktop is sold under several brands (at much higher prices); you could check their reviews.

It's Electrolux, but not offered on their US or UK sites. I can't get info on the vent fan cfm.

~350CFM, 400CFM in "boost" mode.

It’s a useless downdraft. What else do you need to know? Get a standard induction cooktop and put in an overhead vent. It’s the only type of vent that works.