In fact, if the Surface had an Apple logo it would be the Messiah on these forums. Imagine if Apple released a product identical to the Surface but with OSX running of course and Microsoft released a product identical to the IPP. I just know Apple fans would be putting the Microsoft device down.
There are a lot of counterfactuals here. First, if Apple released a hybrid running OS X
and they had threaded the needle of getting OS X applications to run really well in a touch-first environment, then yes, Apple fans would be cheering and lining up to buy it on the first day, guaranteed.
But it wouldn't be an iPad. It would be a Macbook something-or-other.
Second, Microsoft isn't going to build an iPad Pro or anything like it. That is, Microsoft isn't going to build a customized operating system that's not just touch-first, but touch-only, because they have too much invested in the whole Windows ecosystem. That's not a knock on Microsoft - I happily use Windows 10 on a PC at home, Windows 7 on a PC at work and Office 365 all around. Windows is a hugely valuable brand, and they're absolutely right to protect it. Windows RT was a mistake, and one they quickly rectified.
Third, don't imagine that Apple fans are quite so narrow that, "everything Apple makes is wonderful and everything Microsoft makes is garbage." For many Apple fans, slamming Apple's latest design zig or zag is just their way of saying 'Hi'. Need evidence? The iPhone 3G was a plastic piece of junk compared to the original iPhone, the 3GS didn't change anything. iPhone 4? Ugly, squared off, and don't hold it wrong or it won't work! iPhone 5? Let's just keep stretching this thing vertically until I can use it to clean ceiling fans! iPhone 6? Boring, nothing new, meh. All criticisms I heard from Apple fans!
And now, what about the iPad Pro? Over on the "which one will you buy" forum, lots of folks are saying they'll buy an iPad Pro but pass on the Apple keyboard cover and get a keyboard from another vendor. In their mind, Apple got the keyboard flat wrong. Hardly slavish devotion!
Bottom line: MS wouldn't build an iPad-like device that didn't run stock Windows (dilutes the brand), Apple won't build a hybrid, at least not now (not until in their thinking the extra complexity and cost is justified by a better user experience) and Apple fans aren't quite as slavish as you might think!