I have one built by sportsmobile north. I am second owner and I have had it 10yrs. I love it and have not had any trouble out of the sportsmobile part of the van.
The 6.0 chevy engine is great. It has power to spare. Some of them (including mine) have oil pump issues and rear end axle seal issues both fairly easy fixes.
I have had to get a few replacement items and smb north have been great to work with.
If you have any questions PM me your number and I will be happy to call you.