I can definitely verify that for whatever reason, getting large amounts of data through Windows Update is like trying to drink an ocean through a cocktail straw. It's horrible, but this is nothing new. It's always been horrible. I've done many, many fresh installs of W7, both original and the various SP1 integrated/media refresh versions. Doesn't matter. The trick is to install Windows, configure it for SSD and do whatever initial tasks are required, start WU, and then go do something else for awhile, like read War and Peace. Twice. By the end of the second read through, it might be finished.
My experience with Windows 8 is far more limited, but I did fully update a W8 laptop, then update it to W8.1, then fully update THAT, and it was the exact same story. A new star will be born, exhaust all of its hydrogen and helium, and explode before WU finishes updating.
Can't say I've ever had any issues dealing with hard drives. I have however run into the annoying USB 3.0 boot problem. W7 doesn't have native USB 3 drivers, and so out of the box it won't boot from a USB 3.0 port, which can be a problem if that's all your computer has. Unless it isn't. Some UEFIs will allow you to disable 3.0 functionality, which you can then turn back on after the install, others don't. Otherwise you have to manually add the drivers to the installer before hand.
From what I've seen, W10 seems like a fairly decent attempt at a W7/W8 hybrid. Apparently there's STILL no native Class 2 USB support though, because who would possibly need that? Come the fuck on already MS.
Oh, and NEVER, NEVER get drivers for ANY piece of hardware from Windows Update.
