Looks like you will have to revert to Google search after windows 10 upgrade

A thing about Windows 10 is that is gets your account and signs you into almost all services that you use on your computer. Good so far.

When you start searching something on the start menu, or on Cortana, you are directed to Bing. You also get results from Bing presented to your start menu.

Now, here is a screen shot showing the same search phrase on Bing and on Google, which will make you reconsider your choice of searching with Cortana. The edge browser (below) is showing results that have not meaning to what I am looking for, until you look at result number five or so. Meanwhile, Google, on Firefox (above) has three out of four options that are actually about Microsoft Edge review.

Microsoft Edge with bing search vs. Mozilla Firefox with Google search
Microsoft Edge with bing search vs. Mozilla Firefox with Google search