@InduperatorRex I've not used the flip personally, but I hear the criticisms focus on the reliability of the hinge, the somewhat restricted angle of the screen, touch interactions with an upper screen, no dedicated home/back buttons, the fan doesn't have much of an effect, and the fact that it has slide pads (if you don't like those).
On the other end, you get analog triggers, greater pocketability, the the slide pads being more inset makes for a more comfortable grip by default than the 3/3+ design, a bigger battery, two additional programmable buttons (which will be able to be used as back/home buttons with an update), and apparently the black bars on the sides of 4:3 content isn't as jarring when it's on a top screen.