If spending money today I would have a PowerMaster first, then TRC or Hughes, and very very last is Frank's.
What happened to Power Master web page? was
www.powermasterrv.com afaik
If one air conditioner is the primary concern consider a TrippLite LC2400 on the branch circuit.
http://www.tripplite.com/line-conditioner-2400w-avr-system-automatic-voltage-regulator-power-conditioner-ac-surge-protector~LC2400/