After reading all of the reviews It was much more efficient to have the assembly service !!   Wow was I glad I did the technician carefully glued all parts to assure stability and because he does this all the time he was very deficient and familiar in quickly assembling the 2 cabinets side by side.  The 65" tv was mounted above.. 
I was able to focus on my work which makes me money and not try to be an expert at installing.. !! I can sleep at night knowing I hired a service which will protect my investment.