I don't do auto decline, just so I can make counteroffers (and also to see what people think it's worth). I've had pretty good luck with Best Offer, both buying and selling. When selling, I have a price in mind and usually set the BIN a bit higher so the offers will be in my price range. A couple of times I have declined a best offers and maybe had to relist, but I have always ended up with a decent offer in the end.
Also, best offer gives you the opportunity to pick and chose your buyers. I might accept a slightly lower offer from a buyer with higher feedback than from someone who has a sketchy feedback record.