Bing does not blow, stop being so dramatic. I bet all the Bing haters can't even come up with a reason they don't like Bing beyond using Google to find someone else's regurgitated and most likely inaccurate response.
With that out of the way lets get back on topic. Bing is default. It has several nice features built in to your Windows Phone. You can highlight a word or phrase in Internet Explorer and click the search button to Bing it. Image search in Bing is quite amazing as you can pan through image search results much like you do for your camera roll photos. Your apps for Maps and Drive integrate well with Bing.
The only complaints I have about the search button:
1. Local search is a pain sometimes. Unlike Bing on desktop sometimes I need to enter a full address to get local results instead of just street name and number + the phone's location data. To me this seems like a problem that requires someone at Microsoft to flip a switch on their end (no update required).
2. The search button does not search local files on the phone. Hopefully soon.