In the debate on Apple quality, OS X Snow Leopard is usually cited as the high mark in recent OS X quality. Whether or not you believe that Snow Leopard had less bugs than any other release (which I tend to), another thing has changed since Snow Leopard is how Apple distributes Mac OS X.
Snow Leopard was the last version of Mac OS X that required using a disk to do a major update. After Lion, users were able both minor and major to install updates directly from the web. This was done because users frequently never got upgrades disks, and never performed major upgrades on their computer. They would upgrade to the last minor upgrade to the release chain via Software Update, and then be stuck in time. A typical user who’s machine came with some flavor of 10.2 would get upgraded eventually to 10.2.8, and use 10.2.8 on that machine for the rest of it’s lifetime.
Of course, this also meant that they were never exposed to the early, unreliable builds of the previous release chain. Maybe a friend or family member, with an OS X upgrade CD, would eventually do a major upgrade well after the major issues had past. But, for the most part, a large majority of the Mac user base was able to avoid the most unstable releases not because they chose to, but because they were never aware of them to begin with.
I’m not at all saying disc based upgrades were the better way of doing things. Pushing updates over the internet has made life a lot easier for developers, and has made it easier for Apple to push new security updates that require major OS X revisions. But, we’re now pushing users to upgrade to less stable versions of OS X early and often. Average users are being pushed into upgrading on day one by the app store. Even if OS X software quality hasn’t changed at all, the way we’re exposing users to Mac OS X’s release quality has changed. My take? If we’re going to be pushing users to upgrade, we need to make sure there is a great, stable experience that we’re upgrading them to.
(How does this apply to iOS? I’m not entirely sure. iOS 6 was the first major over the air upgrade, and there certainly was an uptick in complaints around then. Before iOS 6 release, iOS users were also infamous for not upgrading because it required plugging their device into a computer, which they either didn’t know, or didn’t want to bother doing.)