Glad you enjoyed the Lars demo!
It does take a second to load, but it's not impossibly long, I've found it to be fairly responsive in testing. It's about where I would expect it to be, performance-wise, for the price tag. Compare it with an R1 or AERO - it's about the same pace.
The reason it gets hot is the screen's power conversion and the processors inside. It's still not as hot as a DJM. ;)