Well, basically, this year's devices are the Tab 4 series, the Pro series, and the Tab S series. Last year was the Tab 3 series and the Note 10.1 (2014 edition) and the Note 8.0.
The Tab 3 series are the least capable of these devices, having specs similar to a Galaxy S2 from 4 years ago. Basically very low end nowadays.
The Tab 4 has better specs. They have budget quad core processors, and aren't exactly top of the line models. At best they're better than the Tab 3, but not by much.
The Tab Pro series is cheaper and more powerful than the Galaxy Note 10.1 2014 edition, but you lose the S Pen, which is very useful on a 10 inch tablet if you plan to do a lot of drawing or annotating on documents/ebooks. No third party stylus can even hope to match the S Pen for accuracy since it's using WACOM technology. And an S Pen won't work on any non-note device so you can't just buy one.
The Tab S is the most expensive and most powerful of the Samsung tabs. The screen is gorgeous as well, if you like AMOLEDs. However, IMO the Tab Pro series has the best bang for buck.
