Vltor is not a chassis.
It is a surplus war era usgi fiberglass stock, cut off behind the receiver and a machine unit is bolted and glued to the cut off stock.
A troy stock has mechanical features and is metal. These features make it a chassis.
One is lighter but offers no "accurizing features" other than bedding and has a major weak point so could fail under rigorous use.
Troy is heavier but built to last. Has rock solid rail options and has no flex so supports the action, lending to potential gains in accuracy.
The M14S-CQB manufactured in my shop is a far better choice over a Vltor and nearly as stiff as aluminum being it is a one piece laminate construction.