A basic concept in race car chassis design is that rigidity adds to the overall performance of the car. But, can the same be said of a racing simulator chassis? Most static (non-motion) chassis are aimed at a introductory budget sim racer. Because of this the chassis are commonly flimsy tube railing imported from a distant land.
One thing that is clear when you try one of these weirdly branded import chassis is the flex and overall cheap feel of the experience. This flex isn't just annoying, it dilutes feedback from the rest of the hardware (wheel, pedals, shifter, etc.).
Diluted feedback means your not getting the most from your hardware. Why waste your money on a chassis that will dilute the feedback and degrade the performance of your hardware? There's' no reason to buy a high tier wheel and pedal set if your going to just bolt it to a flimsy Chinese shopping cart. Buying a rigid chassis and getting the best of the money you spend on the entire setup is the smart choice.
APX chassis are built with the same materials that SCCA roll cages are constructed with. They're also built in California with a real person you can talk to about support, upgrades, and service. You wouldn't go on a real race track with a shoddy chassis so don't go on a virtual one either.