I am kept quite busy with clients running into Windows 10 upgrade issues, invariably from older machines.
i would criticise Microsoft for insufficient information in regard to the process

Here are a summary of some of the issues:
  • Window 10 compatibility appraisal is often wrong, or rather omits items that won't work in 10
  • Some manufacturers such as Asus are not updating their software/drivers for Win10.
  • Older printers won't work
  • Quicktime current release is not compatible
  • Many programs have a send to email function, in many cases this no longer works
  • If you don't have the very latest AV release folks run into probs; must have the current release.
  • Folks running XPMode cannot upgrade

There are other aspects which Microsoft sees as an enhancement but are a retrograde step,

  • eg chkdsk info at boot time is like defrag on Vista - unhelpful!
  • Windows Update - not being able to schedule, some of the very big updates , ie new release, can take forever, and have repercussions on internet usage/costs (not just for laptops either) - not sensible.
  • The way apps are displayed and scroll down is unhelpful and slow.

I could go on, so at the moment I am sticking to Win 7 - in my humble opinion Win XP was the best OS that MS have produced to date, shame they no longer support it. Lets see if MS addresses some of the criticisms of Windows 10 (eventually).