Buggies are definately more durable than Monster Trucks but not because theyre built better. The problem with MT's is that they can be driven over rougher terrain so inevitably they break quicker.

About the harshest thing you can do with a buggy (short of running into a wall) is jumping it. This might sound rough but unless your jumping insane heights or flipping the thing repeatedly, they will take alot of this.

A Monster Truck gets bashed thru rocky areas, off porch steps and other areas which cause a whole pile of stress to the suspension. Add in that MT's tend to weigh more and have big tires ( more stress on everything) and you can see why they tend to break more.

Of course there are those who will disagree because theyve been lucky or baby their trucks but in general these things are true.

( a 2 wheel drive stadium truck is also fairly durable and when stuff does break it's usually simple to fix)