The difference is that the AR15 has military specifications based on the M16. All manufacturers make them to the same specs. Some are better than others.
The AR10 was proposed to the military but was never formally adopted, so there is no "mil-spec" that was followed. Each manufacturer can, and does, make modifications that they think improve the design or, in some cases, can keep people buying proprietary parts.
Again, please give a review of the product if you can.