I've been storing some household items at SPS in Herndon (they've moved to a different location on Spring Street) for a several months now and am always impressed when I go there. The staff is extremely helpful and the storage facility is always clean and well-lit. In addition, the building is accessible with a loading dock and push carts available for use by the clients. I highly recommend SPS in Herndon.
Pros: Professional, Courteous Staff; Clean, secure facility