I have put together some figures on visitors to the PerfectTablePlan home page by operating system over the last 6 months. For clarity I have left out Windows NT, Linux and some of the other OSs that don’t figure very prominently amongst visitors to this site. I think these figures show some clear trends. You will have to click on the graphs below to see them at a readable size.
The overwhelming dominance of Windows XP is clear for all to see.
If we remove XP from the graph we can see that Vista market share is rising steadily, by about 1% per month. There are also clear downward trends in Windows 2000 and 98. Windows 2000 users still outnumber Windows Vista users, but I doubt this will be the case for much longer.
Windows Vista has a long way to go to dominate the market. Personally I don’t see any compelling reason to upgrade to Vista, unless you are a developer supporting customers with Vista (even then you might be able to get away with running Vista inside a VM). Indeed there has been a certain amount of backlash against Vista. But make no mistake, Microsoft are the Borg. Relentless, merciless and unstoppable. Sooner or later your app will be destroyed or assimilated by Vista. If you haven’t thought seriously about supporting Vista you had better start soon.
Resistance is futile.
Successful Software 
I remember when I *couldn’t wait* to install each new version of Windows as it came out. Windows 95 was a huge improvement over 3.1. Then I got a job and realized that Windows NT4 was way more stable than Windows 95. With Windows 2000, there were tons of new features, a slicker interface, and again, better stability (less blue screens) than NT4.
Windows XP seemed like a slicker version of Windows 2000 but with lots of goodies pre-installed like remote desktop, and it was more customizable, but again, to me, blue screens and computer locking up was virtually non-existent. I like XP.
I’m scared to upgrade my computer to Vista though. I’ve read tons of negative reviews, mostly with respect to the constant security pop-ups. And again, I like XP, it works great for me.
So I won’t upgrade until I’m forced to for business reasons, or if after running it in a VM for a while I find a reason to because I like it better.
In summary, something has changed regarding the release of a new Microsoft OS. Instead of rushing to upgrade, I’m reluctant to. Or I’m getting old.
My new Vista box bluescreened twice within an hour yesterday. I don’t remember the last time my XP box bluescreened.
>>If we remove XP from the graph we can see that Vista market share is rising steadily, by about 1% per month.
I guess this is what you would expect from the PC replacement market, I doubt you can buy a PC in PC World without Vista now. In fact at that rate people are replacing PC’s every 8 years which seems quite long to me.
>people are replacing PC’s every 8 years which seems quite long to me
I would guess that developers and gamers probably replace their PCs every 2-3 years on average. I don’t what the figure is for non-techies though. I wouldn’t be surprised if the lifespan of a non-techie PC is 5+ years.
Something else you might not be aware of is that a lot of software just doesn’t work in Vista. For example Quickbooks 2006 does not and will never work with Vista. Intuit has basically said that if you want to run Quickbooks in Vista, you’ll need to buy 2007, they won’t update 2006 to support Vista. And I can’t blame them!
We went through the effort of buying Vista boxes and upgrading LandlordMax to support Vista and it wasn’t easy. It took a lot of effort, it was our biggest update in history (we’ve been in business over four years now). It wasn’t just our code that needed upgrading, we actually had to upgrade the Java Virtual Machine that runs beneath our code. And even then the latest version still has some visual bugs with Vista! If you’re interested you can read the full here.
It wasn’t pretty. And it’s because of this reason I can see a lot of software vendors not wanting to support Windows Vista. You look at the customer base and the effort required, the cost to benefit equation just doesn’t work. You’re basically doing it to provide your customers a path for the future. And hopefully along the way you might acquire some customers from your competitors who haven’t yet upgraded to support Vista!
If you are writing enterprise software, I think you have at least 5 years ahead before thinking to go there. And before that, Microsoft will also try to push the 64-bit edition of Vista (which has a ton more compatibility problems for third-party software than the 32-bit edition). And guess what, they are already cranking up to shipping a newer OS within two years. All that with the rise of virtual operating systems.
The best thing? Microsoft compatibility team is doing the bulk of the work for third parties out there, by keeping WIN32/OLE/COM/GDI and all that stuff equally working than on previous OSes.
So why the stress?
If you are in a niche though, and the heart and soul of your income is to live on the edge, consult only about the very latest technology bits, and so on, then it’s a no-brainer. Someone like that has already taken the Vista train 3 years ago (if not more).