I have replaced the IObit Start Menu 8 in my Windows 8.1 PCs with Classic Shell 4.1.0.
Classic Shell 4.1.0 is more stable, and more feature rich than IObit Start Menu 8. The Classic Start Menu in Classic Shell 4.1.0 can also display properly in high screen resolution of 3200x1800, but the IObit Start Menu 8 appears tiny in such high resolution screen.
You can download Classic Shell for free here.
The key component of Classic Shell is Classic Start Menu, which brings back the Windows Start Menu in Windows 8/8.1 similar to IObit Start Menu 8.
There are many settings you can play around in Classic Start Menu 4.1.0.
Besides, Classic Shell also includes Classic Explorer which will add a handy toolbar to Windows Explorer.
This Classic Explorer toolbar is configurable too.
The 3rd component is Classic IE, which adds the following functions to Internet Explorer: