Since I have one, I can comment on the X4S. If you have the opportunity to ride a lot of trails, I’d say it’s a good choice to add to your collection(?) of boards, but it’s important to understand its potential faults. It’s big, heavy, and has a high center of gravity that makes it unpleasant to ride on the street at speeds above 22mph. It’s also a little underpowered, and the ESCs (Ling-Yi) are not as smooth as I’d like. Also, the “shocks” are really just spring guides as they the do not have any internal dampening. I’m not sure compression or rebound dampening would add much to the ride experience, but I intend to try a shock swap to find out. While it’s a board that should be considered for almost exclusively off road riding, it’s not a good choice for the kind of high speed with jumps that you’d do on something like a Trampa. With its bump eating suspension travel and large diameter tires, it’ll allow for some exiting trail speeds for sure, but you’re not jumping the thing or roosting dirt over the tops of tight berms as you try and keep up with SurRon riders. Really all of this should be obvious to anyone taking a close look at the boards specs though, so none of them came as a surprise to me. I just thought I’d point them out if you’re just beginning to look into one.
There are some things that weren’t obvious to me before I bought, and I’d put them in the win column. One is that it’s actually quite maneuverable. It has a tighter turning circle than my my Prototipo, Kaly, or Endeavor. Of the boards that I’ve ridden, only my DKP equipped Ownboard will turn tighter and that was after setting it up loosely and swapping the stock bushings out for Riptide and Orangutan. The 10 tire and wheel combo will roll over things without much notice that would otherwise toss you with even 8” pneumatics. I sort of expected that, just not to the degree that I got. Also, it’s actually simple easy to work on (which is good because it requires maintenance such as greasing the shaft ends and checking fasteners for tightness) and to tinker with. I’ve already done a couple of mods to address stability, and as mentioned with the shocks, I have more mods planned. It’s also more durable than I expected, and repair parts are available if you do manage to break something. If you’re in the US, Propel’s tech support and parts guy is accessible and seems to be a super good dude.
Hope this helps, and please feel free to reach out if you want more ownership input.