Replacing my 15 year old OTR microwave that has venting behind cabinets leading to a roof vent. The venting never worked well (smoke in house cooking most everything) but I need a microwave here so am looking for a good one with the most powerful vent fan. I’ve come across 2 so far — Kitchen Aid Model: KMLS311HSS (500 cfm fan) and a Samsung Model ME11A7710DS/AA (550 cfm fan). Opinion please? Any others? Which one will actually vent better??