I use it all the time and it works great. Most times I get the money in my PayPal account immediately but occasionally have to wait a month or two for it. There used to be a limit of 20 transactions per account (why I have multiple accounts on eBay) but they upped that to 40 I believe. Combined with 2% eBay bucks I get 10-12% discount on pretty much anything I buy.
A lot of people obviously aren't getting it, as I often see people bid higher on auctions than they could have bought the same item for BIN if they'd used Bing. To be honest there are people who bid more than they could buy the same item BIN without Bing, not sure what they're thinking but I wish they'd wise up because they don't leave any crumbs for bargain hunters like me :-)