This one is right up my alley. Tart apple up front with the depth of vermouth and sloe gin on the finish. It strikes a perfect balance of being quaffable without you losing interest after a few sips. I can see how you could serve this over ice as well, or even top it off with soda water during the summer.
We sometimes throw in a splash of a deep and brooding but sparkling Shiraz. For the bubbles that you insightfully recommend. We don't think that Persephone would have been satisfied with just soda.
Great drink all around!