I own the MTXL and it is a blast. Things to get with the truck.
1. A better radio system that allows for precise control of settings like steering balance etc. The steering on it as standard is poop. It has the turning radius of an 18 wheeler until you get a radio where you can set a narrower radius. I got a used Ko-Propo which has turned out to be one of the best investments I ever did in my RC hobby.
2. This
https://www.amazon.com/Hot-Racing-DBL4801-Aluminum-Steering/dp/B014Z2ARJW The one in the truck WILL break. I find it laughable that they give you aluminium horns for the dual servoes and brags that its because of all teh power from the servoes (which they have, 60kg or so of it) and then they turn around and connect those fine alu servo horns to this poopy little piece of BS plastic. I bet the designer of this bit have to wear a special helmet indoor.
3. 100.000acu silicone for the front and back diff and 500.000 for the center diff.
I have seen few trucks who will take as crazy abuse as this truck though. Other than these few items and a few smaller peves the truck is fantastic. It is heavy and brutal, yet with a better radio it is surprisingly nimble. It will do crazy airs and put up with practically any terrain and condition you throw at it.
Botajell is a great guy. He has some pet peve against electric cars which is his to enjoy. I don't care because for gas/nitro people his information is high quality and he is always willing to take time out of his day to help anyone who asks. Not just on youtube but via his private email too.
He has had almost all the 5 scale that has been out and he thinks the MTXL is the best bashing 5 scale ever made. I have not tried or owned but a fraction of those and I am also sold hook line and sinker once these issues mentioned have been fixed.
The thing is, the control issue may just come down to personal taste and preference. Botajell runs the truck with the default radio system and have no problems with its kinks. I on the other hand, cannot stand them.
Also I don't see this as a monster truck. Not many RC's that call themselves so really are. The MTXL is a new class. Closer related to a truggy than a monstertruck.
Finally. Prepare for a shock. These trucks are fiddlesticking HUGE!!! Videos do them no justice. I had only seen them on videos and when my own (almost couldnt) get through the door I was gobsmacked. It is enormous. more like 4 scale.