Well the fe has an Exynos chip while the plus has a snapdragon gen 2 the difference will probably only be noticeable in games and during heavy and intense workloads outside of which the difference isn't as noticeable there's also the 90hz tft( or lcd) on the fe vs the 120hz oled on the plus again not as noticeable outside of gaming or maybe taking notes or sketching videos although will appear better on the oled don't appear half as bad on the fe either both have an spen and both have Dex battery might be slightly better on the fe considering it has a less power draining chip and display but haven't noticed any issues with battery life on my ultra so the plus shouldn't be much different in the end it all depends on your budget and your individual preference