I've had the exact opposite experience. Admittedly it's not a completely fair fight (Google has years of data to tailor results to me, and I know on some level what sort of queries work from experience), but it's common that if I use Bing (it is the default on my Windows Phone) the thing I'm looking for won't be on the first page of results. Using the exact same query on Google almost always has it in the top 3 results.
It's not useless by any stretch, but when (very roughly speaking) a quarter of my searches end up with me going to Google anyway, there isn't much value in trying Bing first.
It's not useless by any stretch, but when (very roughly speaking) a quarter of my searches end up with me going to Google anyway, there isn't much value in trying Bing first.