My three year old grandsons have these:
They are used as 'indoor' toys as they have large Tonka toys for the sandbox.
While down at my son's house last weekend we played with their RC trucks.
Had a blast with them. They do require supervision with the little guys though.
My son got a new RC truck and it was a TOTAL blast to drive, so much so I got one for myself so I could be a part of the fun when down there.
It was under $160 delivered to my door next day which blew me away. It's a real big boy toy though as it goes 55kph when on full power, a setting I'm working up to.
The toys in the first photo seemed well built and were fun to play with inside. Not sure how well they'd hold up to outdoor use though.