Here a 3DOF prototype from RaceStart, I tried in Paris during the "Mondial de la Simulation":
The total cost is around 25.000 € and I've been told that each actuator costs 5.000€ (they have been tailored on purpose).
The Heave feeling is very good!
It's not good for small reactions
Too much angulations for my taste!
It's rather noisy...
in conclusion, my 2DOF is the highest quality/price ratio!
IMO, the DIY approach is the best for simulators.