OK after looking at both systems.
I like the Mistking better.
If something breaks like the pump it can be easily replaced or repaired.
Unlike the exoterra that is all self contained.
And you can use what ever tank you want for the water supply.
Where as the exoterra is provided and limited.
And the mistking is upgradeable.
As far as actual use and durability I can't attest to the quality of either.
Since I don't have any live plants I chose a fogger for my humidity control.