No, phase switch I found to be inadequate. MHO, I think subwoofers need to have continuous phase controls to seemlessly blend in with the speakers at that crucial crossover region. When I had the following setup:
MSB Link DAC III -> MF A3 pre -> Sunfire True Sub Jr. -> MF A3 power -> Spendor S3/5
...I didn't find the sub truly disappeared until I put it between the pre and the power and dialed in the exact right value. I realize it's not really a phase control any more, but rather a micro-delay, but IMHO, that's preferable. Despite what most would perceive as a radical difference between the Sunfire and the Spendors -- and the fact that I was listening to the Spendors in nearfield, and the sub was a good yard away on my right -- the sub absolutely disappeared.