Pat, the only objection I have to check valves is the additional restriction they present to the system just because of their structure and turbulence they generate. Of course you could go grossly oversize on the valve but then the cost goes way up and I'm a cheap guy. But, when you consider the investment in equipment and the pool, one shouldn't care about another $20 or so. Also, your comment about the multi-port valve, this is on the pressure side of the pump. Air wouldn't come in, water would be blown out. Air leaks have to be on the suction side.
Al