Since Windows 9 is expected to be released , just a shout out question , is there any news of Win 9 supporting SP2 ? and the upgrade being free like the win 8 to 8.1 ??
Unless Microsoft decides to change things at the kernel level, all Windows 8 drivers would work under Windows 9 without any issue.
So assuming that Windows 9 won't be supported on the Surface Pro 2, and assuming the above point, it should be working fine.
The reality of things is that unless Microsoft just changed (I doubt it), Microsoft will provide full support for Windows 9 on the Surface Pro 2. Microsoft has a history log and reputation of doing so, especially that the Surface Pro 2 is PC hardware "and nothing special", I would highly doubt it to not work. I got Windows 8.1 Update 1 installed on my 5 year laptop, where when I got it, Windows 7 was not out. It was running on Vista. I recall the days of Zune, where Microsoft continued to support the very old Zune models previously released, and continues to add features to them.
So, I would be really surprised if Windows 9 would not work on it. Maybe the public beta version might have missing drivers (which is normal.. manufactures will at work then), but the official release should be fine.
Microsoft is looking like they are offering discount to early adapters as well. Windows 7 got 50% discount for the Pro, and Home Premium got 60% off. Windows 8 Update was 40$. So, perhaps, Windows 9 will have similar special at release, so look out for that.
The upgrade would definitively not be free, unless Microsoft does a massive change of direction on how to get profitable, I doubt it.
Windows 8.1, and 8.1 Update 1 were free for Windows 8 users because Microsoft changed. It used to be that every 3 years you had an update of Windows (XP the exception where it lasted 6 years due to delays of Longhorn project (Vista)). However, with the rapid rate of other OS, and the technology world we are in, Microsoft, to stay relevant have now changed to offer yearly update. So, it is a new Windows every 3 years, and a free sub version update every year, and sub sub version (like Update 1), earlier.
It has nothing to do with Microsoft fixing mistakes.. well maybe the sub sub version (Update 1), but not 8.1.
Service Packs doesn't and never did traditionally offer a wide range of new features. They were just a large set of bug fixes and minor GUI improvements, and a grouping of old updates packages put together to make your life much easier when comes installing or re-installing Windows on a system.