I am a computer teacher and hence I have to deal with different types of sofwares, for this I need a fast operating system I am using windows 7 professional since 6 years during this time period windows 10 was launched so I shifted to windows 10 which completely slows down my pc sofwares life ps CC, lightroom starts to leisure and my pc starts to hang on alittle bit fast action commands this is only due to windows store that is added in windows hence making it sutable for PCs with higher rams and big octa core processors.
if you have your pc with around 2 to 4 gb ram you should always go for windows7 and if u have i3, i5, i7 pcs then u can try windows 10.