- Solid physical attack and defense, giving it a lot of power behind its attacks while still being able to tank a hit or two.
- While not the best, its speed is good enough for it to outspeed at least something before going down.
- Rock is decent as an offensive type, which easily allows Stonjourner to contribute at least something offensively.
- Its speed is again, not the best, which leaves it easily overwhelmed against more offensively-geared teams.
- That special defense is absolutely atrocious. Any special attack WILL heavily damage it, or in most cases, OHKO it.
- Its typing is easily exploitable defensively, which, combined with that horrible special defense, Stonjourner likely won't last long at all.
- Power Spot is useless in Singles, essentially giving Stonjourner no abilities to make use of.
- As an offensive Stealth Rock setter, it faces great competition from Excadrill and Tyranitar, which have better typings defensively and offensively as well as generally better stats, while defensively, you're much better off using Ferrothorn, which has a better typing and a more beneficial ability in Iron Barbs, not to mention its access to actual recovery. Even more niche ones like Coalossal, Copperjah, and Runerigus work better.
Stonjourner ends up being so specially frail and, to an extent, slow, that it's not going to make good use of Dynamax. Its attack stat isn't also particularly impressive, to add insult to injury. Max Rockfall isn't any good because even with the Sandstorm boost in Special Defense, Stonjourner's just going to die to all special attacks. Just use Gyarados, Hawlucha and Excadrill if you need to Dynamax a Pokemon.
How will Stonjourner do in OU?:
Terrible. Absolutely terrible. Although Stonjourner carries nice stats on the physical side, an exploitable defensive typing as well as an atrocious special defense stat leave no reason to actually use this thing over other, more consistent, Stealth Rock setters, like Tyranitar and Excadrill, or maybe Ferrothorn if you're more of a defensive player. Hell, even more niche ones like Coalossal, Copperjah, and Runerigus work better than Stonjourner. They have more beneficial abilities as well as better stats across the board in general, and carry more support options as well, be it Spikes in the case of Ferrothorn and Coalossal, Rapid Spin in the case of Excadrill, or Toxic Spikes in the case of Runerigus.
Unless you're going to use this for memeing players, don't use it OU or UU. Maybe in RU, NU, or PU, it'll have a better niche there.
Go to the Cons and How will Stonjourner do in OU? sections, and you'll see why it isn't that good.