Every time a new version of Windows is introduced we lose something, and invariably there are some initial bugs that have to be worked out, but I was not expecting bugs in the basic apps that are included with the OS!
The first major bug that I have run into is File Explorer under the Windows 8 Desktop. With the Start Button being missing, File Explorer ends up having a bit more go-to use than in the past, but what I discovered was that you have to wait until the system and Desktop are fully initialized prior to running apps -- including File Explorer -- or they will lock up and freeze on you. If you leave File Explorer in its icon state in the task bar for too long, it will also lock up, becoming unusable, and what is worse, you can not kill it with a right-click close-program command!
Considering the fact that File Explorer is a native application for this OS that should not be happening, and even so it should have been immediately patched. In addition to that, apps like Firefox also lock up if they are run too soon or you try to open more than one app at a time, which tells me that there is an issue with the file handlers in the OS -- something that Microsoft had better get very serious about patching very quickly if they want to keep users -- and early adopters -- happy.
Another area that I found to be overly difficult is the Virtual PC and Windows XP system that users of Windows 7 will be very familiar with... The whole idea in Win7 for the Virtual PC was to permit users to continue to use the software from Windows XP that they had been using prior to the release of Win7 -- a good idea -- and in fact Microsoft went out of its way to see to it that adding the Virtual PC and Windows XP support to your copy of Win7 Business or Professional was a snap. Not so with the Home Edition however, which required upgrading the license of your OS first.
Still getting WinXP apps -- and games -- to run under Win7 was trivial when compared to the same desire on Win8 -- which does NOT have that smooth and automatic configuration to add XP and a Virtual PC to the OS. Oh, it can be done, but it requires the user jumping through a number of hoops, including installing a licensed copy of XP, which means that the average user is simply not going to be able to manage this. Word of mouth on the hostility of Win8 to XP Apps is already circulating online, with the likely result being a reluctance of PC owners who still must use XP apps to upgrade at all.
While getting XP based apps and games to run under Windows 8 has been a major chore, getting apps and games for Win7 to run was no issue at all, so if you happen to not need legacy apps, you should be OK - but it is becoming increasingly obvious that the move to Windows 8 basically means abandoning all that came before Windows 7.
That is something for you to consider if you plan on upgrading.