MKBHD is very well known for quality videos among Android users, here's his take on the iPad Air:
https://www.youtube.com/watch?v=Hr8E-_yU2YA . And iOS 8 coming in the Fall
https://www.youtube.com/watch?v=lXPvnhNcMs0 . Here's is Android Authority's video on the Galaxy Tab S:
https://www.youtube.com/watch?v=MKh_eF95IxI . And, here's a video on Android L
https://www.youtube.com/watch?v=y9ue7TNpxS0 . Personally, I'm an Apple guy when it comes to mobile. I've had great customer service with them, and rarely come up with problems with my iPad. I use my iPad all day and it usually has power left over at the end of the day unless I've used Skype all day. What I've heard is that Android has more apps, but less of quality to compared to iOS. Usually, Devs make apps for iOS first, and then port their app to Android. Sometimes this port is actually made for Android, or it can just be done rather poorly. Additionally, you've chosen a Samsung device here. I frequently go on /r/Android, and a big complaint I see on there with Samsung Devices is Touchwiz. They find that it degrades from Vanilla Android. You're not using a Google device, so you won't receive Android L when it comes out either. You'll have to wait for Samsung to update this device and their software to Android L before you can get it. This can take days, or maybe even weeks or months. Some Devs have spoken about how quick Android L is on the Nexus 5. It's quiet quick and works very well, but a comment that kept coming up was that it still wasn't as 'snappy' or responsive as iOS 7 is. Of course, Android does allow for more customization among the OS and you have access to widgets and can change default apps. Apple has a set amount of devices and, unlike Android which has many manufacturers and many different devices. This can be great for Android, giving you a great amount of variety among the devices. However, you'll find less accessories from 3rd parties due to the different dimensions of all the devices. Honestly, the OS comes down to personal preference. My family, and most of my friends all use iOS products, and the ecosystem between them works great. It offers a great amount of quality apps, accessories, quality build and materials, and a snappy and fluid OS. They don't have the greatest specs, but Apple show that with proper software optimization, you don't need a bunch of hardware crammed into a device to make it efficient. However, iOS lacks in open-source, customization, and the OS is rather locked down and under complete control by Apple unless you Jailbreak. Android is like a PC in your pocket. It offers many utilities, high-end specs, and a very large range of apps, the ability to download apps without using Google Play, and other things such as emulators which you can't get on iOS. However, many manufactures put on software, such as Touchwiz, onto Android which some users may find degrading from the overall user experience, and the hardware usually optimized that well with software. I believe it will come down to personal preference of the OS when it comes down to this tablet. Both the iPad and the Samsung Galaxy Tab S are high-end devices, and I don't think you'll be disappointed with either device.
Edit: Here's a UI designer's perspective on Android coming from iOS:
http://jacksonfish.com/2014/05/22/a-use ... o-android/
