They were actually removed in Win8.
If you are building a system, the OEM version is what most people will go with. There really isn't a reason to buy the retail version.
I'm scratching my head here, so let's talk.
I can see someone still recommending 7, because it's tested and the UI is immediately effective on traditional devices out of the box. I can see recommending 10 because it's the new hotness, and as such has the most potential life left in it. My problem is why in Hades windows 8.1 would be considered. Yes, they moved the limits on the base version (or whatever you want to call it, due to Home disappearing that generation) to 128 GB, but why does it matter? It's like touting the benefits of Vista three months after 7 launched.
OEM is a pain if you've ever got to change hardware. In three years you'll want to update that CPU and motherboard, and your OEM license doesn't allow you to change motherboards. Heck, I experienced this with my x79 build (the Gigabyte UD5 board sucked), so I spent a few extra dollars to get a retail copy. One call to MS, and my new board is legally installed with a working OS. $20 out of the gate saved an expenditure of $100. I'll take an extra $80 in my pocket, for a slightly better upgrade capability. If your computer will never have the CPU and motherboard changed, more power to you. If you're realistic, choosing an OEM copy, and being a compulsive upgrader, isn't cost effective.
The counterargument is people lie to MS. It isn't hard to get them to reactivate an OEM copy when you upgrade, as long as you indicate your motherboard fried. I can understand that sentiment, but sometimes it's easier to go to tech support and simply tell them to give you what you paid for, rather than weasel your way through getting a reactivation. Only time will tell with windows 10, but I'd prefer to have a Teflon backside and not need it, rather than need it and not have it.
