For me, the 8.1 upgrades have never created an issue. But some folk have reported issues and you won't know until you do it.
I have a Samsung Series 5 DP500A2D 21.5" Touchscreen All-in-One PC running Windows 8.
I don't want to download Windows 8.1 directly on the computer because of download limits on the Internet connection it uses but I do have a Windows 8.1 installation DVD created using files downloaded from this website: http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media (64 bit version - same as I'm currently running.)
I haven't upgraded to Windows 8.1 yet as I have two concerns:
1. The product key for Windows 8 that was pre-installed on the machine is apparently embedded in the motherboard so I don't have the number on a sticker. Will I run in to any problems by not having it? I can obviously get the Windows activation ID through the control panel.
2. Will upgrading to Windows 8.1 cause any issues? I'm not bothered about losing the pre-installed Samsung apps but more that the Bluetooth, Wireless, DVD drive etc. all carry on working.
Also are there any issues I might come across if I later upgrade to Windows 10?