I have used them, but my cider's are all still in the secondaries. The "tasting" leftovers from racking proved to be real dry, but not puckery.
Yes, they are expensive too. I had several 5 gallon batches going, so I made the plunge and bought them. I used the Wyeast cultures, and I even pitched a second batch on the lees from an earlier batched. Both ciders were racked at the same time. Time will tell.
On Deck - Crabapple Wine
Secondary - Pomegranate Wine, Red Table Wine, Wild Fox Grape Wine, Blueberry Wine, Surly Furious clone
Bulk Aging - Brewtopia Barleywine, Sugar Beet Wine