I just pitched a new batch on my first Apfelwein yeast cake, mostly because I didn't have any spare yeast lying around & wanted to get another batch started pronto. Mail order would have taken a week or more with ridiculous shipping costs.
It took longer to get rolling than I expected, but about 30 hours after putting it on the yeast cake I got great fermentation going that looks good. It smells fine -- in a bit over a month I'll tell you how it tastes, but I think reusing the yeast cake is a fine way to go.
Currently On Draft: Bamberger Rauch Dunkel, Belgian Blond, Pilsener Urquell clone, Smoked Porter
Bottled: Concord Pyment, Mi'Apa Sparkling Mead, Chimay Blue, Old Simcoe American Barleywine, Old Cantankerous
Fermenting and Conditioning: Pseudo-Decoction Munich Dunkel, Left Hook Bitter
Recently Kicked Kegs: Fresh Hop Pale Ale, Citra Rye IPA
On Deck: Old Rasputin, Northstar IPA, Ur-bock Dunkel