It depends on what you need, to me the Pe8 gets cannibalized by the PE14. I use the PE14 just like I use the PE8, for very tight precision polishing on classics or contouring very sharp angles like fins. Also keep in mind the PE14 might be bigger but offers the most control of ANY polisher out there besides a Festool rotor. The advantage of having a rotary for tight precision polishing is not having to worry about throw which can impede and even damage raised/tight areas. The PE14 offers slow start FROM 600 which means you could run it at around 2-300 on partial throttle. To me, the most important feature of a rotary is the soft start. I like my Mini, but it does tend to get cannibalized by the Nano.
It`s kind of like having a laptop, tablet, and a large size smartphone. You tend to reach for the extreme, rather than the middle because you have the choice.
My line up right now
Flex PE14
Dodo Juice Spin doctor V1
Rupes 21 MKII
Rupes 15 MKII HD
Rupes 75 Mini
Rupes Nano LN
Sold
Flex 3401 - Too much vibration
Flex PE8 - Too small of a machine for not having a soft start + 1000 rpm starting is not always great...
Rupes 21 Legacy - Only machine I regret selling (I gave it away to a friend; however I plan on getting another)
Rupes 15 Legacy - The MKII was just such a step up!
Griots Garage BOSS 21 - By far the most powerful machine I`ve ever used. However, the Rupes MKII was smoother.
Griots Garage 6 inch II - Broke
Griots Garage 6 inch III - Replacement, best bang for the buck machine out... it`s not a Rupes, though!
Griots Garage 3 inch II - Not enough power, great sander @ 8mm throw
Metabo 14 Rotary - Too wonky