Is it hard to put this base together?
Relatively easy when you follow instructions, but it is heavy.
Does it have any special features?
Yes, several including:
Does it include wall-hugging feature?
How long is the warranty?
25 years with first 5 including parts and labor and remaining 20 on a limited basis.
How high off the ground is it?
Legs adjust to heights between 6-10 inches.