While I've only used Vyking Ship's services twice now, I'm already highly impressed with their services, benefits and most especially the outstanding custom service. For example, when I had questions in need of answering, the agent assisting me went and contacted a shipping company on my behalf just to get the information I needed.
Not only are customer relations top notch, but so are the services. My favorite being the half-a-year storage that's offered for all packages without any cost. It's a life saver if you intend to ship several items to their warehouse at different times.
The only real con I can list is the fact package consolidation, while great in-general since its only a meager dollar fifty to repackage items into one shipment, seems unnecessarily expensive when you're dealing with small objects such as trading cards that're contained within mailing envelopes. That said, TCG aren't very likely to be used with Vyking Ship's services, so this isn't that big a concern.
To summarize: Exceptional customer service, great value for repackaging (though can come as expensive when dealing with extremely small items), complete honesty with prices, and a free six months of free storage for your packages.