If you're a developer and use Windows for any reason then Windows 8.1 is a huge improvement over previous Microsoft operating systems. Only Windows 2000 compares. The built in type-1 hypervisor alone is worth the upgrade. Hyper-V is faster than virtual-box and other is becoming a real competitor to VMWare and Citrix products.
Maybe, but 8.1 killed all of our VS2005 projects. If you are a developer that doesn't want to do upgrades on potentially fragile build files it is not a god send.
