Here are the diffs:
http://www.pocket-lint.com/news/134655-samsung-galaxy-tab-s2-vs-samsung-galaxy-tab-s-what-s-the-difference
The S2 models are slightly smaller but use a 4x3 aspect ratio (so wider in portrait, taller in landscape, with wider top/bottom bars when viewing widescreen video). The screen resolution (and pixel density) is lower than on the older ones. The batteries are smaller.
Unless you don't like the 16x9 aspect ratio I don't see any reason to buy the newer ones (and I really appreciate the drop in price prompted by the new ones).
http://www.pocket-lint.com/news/134655-samsung-galaxy-tab-s2-vs-samsung-galaxy-tab-s-what-s-the-difference
The S2 models are slightly smaller but use a 4x3 aspect ratio (so wider in portrait, taller in landscape, with wider top/bottom bars when viewing widescreen video). The screen resolution (and pixel density) is lower than on the older ones. The batteries are smaller.
Unless you don't like the 16x9 aspect ratio I don't see any reason to buy the newer ones (and I really appreciate the drop in price prompted by the new ones).