Bing & Yahoo are teamed up. If you create a campaign on Bing Ads you show up on both Bing.com & Yahoo.com properties. Traffic is often both higher quality and much cheaper than compared to Google. Bing is very forgiving and approves almost any campaign.
About 1/10th of the traffic, Google can provide. Their interface is complete garbage and needs an update. Can’t scale your campaign very much once you do find a winner.
If you believe Paid Search is the way to go for your business then I would definitely test out Bing ads. Your chances of finding a winner are much higher and will cost you much less. However, don’t expect to be spending over $100-200 a day in most niches.