Having seen the comments regarding the removal of the RT upgrade to Windows 8.1 from the Windows app store I was surprised to see it had re-appeared last night.
Late this morning I started the upgrade. Its a 2GB+ download so make sure your Surface is plugged into the mains!
The download wasn’t a speedy affair but it progressed and immediately cut into the upgrade. Everything seemed to go well – usual questions regarding accepting T&Cs and configuration. Express seems to work OK.
The usual Windows.old is left behind (2GB+) so used Disk Cleanup to delete that through the Clean up System Files button and selecting to remove previous windows installations – see http://windows.microsoft.com/en-GB/windows-8/how-remove-windows-old-folder
The apps that I had installed appear to be preserved and at the moment everything looks good. A painless upgrade for me. Hopefully the earlier reported issues are all resolved.