I got the Tab S 8.4 for Christmas (Actually had the Nexus 7, but returned it after one week because of a line of dead pixels and didn't take long to realize that 32 GB and no SD slot wasn't going to work for me) It's got 16 GB internal and of course the SD slot so I figured I'm good... Here's my problem with it... Most of the files are Odex and you can't move them to the external card with Link2SD so my system partition is quickly running out of Space.(see attachment) So I guess we'll see how that goes.
You people who bought a pro and feel like you got screwed, I get it. Same thing for me sort of, I bought the S4 and then like a month later the S5 hit the Shelves. But this is how I look at it: My S4 is still a great product and just because something better came out doesn't detract from it. There's always going to be a better, newer device right around the corner.
Final thought... It was indeed very confusing when I was looking at Samsungs line of tablets and I had to research just to figure out the differences, but that's Samsung for you, seems like they just throw stuff out there and see what sticks. I will say that I thought the Tab S was too much money, but I didn't pay for it myself. Oh and I like the screen personally, you can tone it down in the settings... OK then.