I've owned both generations of the Nexus 7, the Galaxy Note 10.1 (2014) and the LG G Pad 8.3 (GPE) and the LG is by far my favorite. It has the optimal size display for a smaller tablet with much smaller bezels than the Nexus, great materials and build quality, expandable memory and runs stock Android. Only negative is the display--while sharp, it's on the warmer side, almost yellowish in tone. TBH, I only noticed when putting in alongside the Nexus 7 and an iPad Mini.
The latest generation Nexus 7 is also very nice--I just find the 7" display too small.
The Galaxy Note 10.1 (2014) is a big step forward from past Samsung offerings but still has some noticeable flaws. TouchWiz is still too heavy handed with features of questionable utility and performance and results in an inconsistent and occasionally laggy experience. I also do not like the use of hardware buttons as it makes use in portrait orientation a PITA. The S-Pen works well but Samsung's accompanying software needs some improvement and expanded compatibility (more multi window compatible apps and syncing outside the Samsung environment).
I'm curious about the recently announced Samsung Tab 8.4 with it's super high res display but worry about the hardware buttons and Samsung's UI skin.