Forums can be a great source of information. If you want to know how well a product is doing, if there are any issues and how frequent or severe, just search around associated help forms. A current topic right now is how Windows 8.1 is refusing to upgrade on some Windows 8 machines running older hardware specs. I haven’t personally seen any official or editorial reports as to why this might be, but the forums do end up shedding some light.
Apparently, Microsoft has altered the System Requirements twixt Windows 8 and Windows 8.1 to include an additional item affecting some older CPUs and motherboards.