If you are deciding whether or not to upgrade to Windows 8.1 from Windows 7, you need to consider various things. The first point to bear in mind pertains to you if you're running a business and are installing Windows 8.1 onto multiple computers, all of which will need legacy apps and services.
If this is the case, Windows 8.1 may not be an advisable choice unless absolutely necessary. While Microsoft has implemented some more mouse-friendly features, the operating system remains predominately designed for a tablet with an awkward transition to the Desktop mode when legacy apps are called upon.
Businesses still rely on some legacy software, no matter which sphere they operate in. For example, Microsoft is still yet to produce a proper, dedicated Windows 8.1-ready version of Microsoft Office, one of the core suites of apps used around the world. When the Office tile is tapped, the whole OS switches to Desktop mode, a jarring process that can be confusing and is in no way smooth.
While legacy apps are still compatible, the process of using them is confusing and feels, above all else, unpolished.