I can't speak to the m16 style but I have 2 da5.56 ar's and the fit and finish is as good as you could expect for 599$-699$ my local smit spoke highly of the gun and the reliability itself, maintenance a little boorish certain things canada ammo did to change it makes stripping it a little tricky . I have actually never shot either one, I will be modding up mine quite a bit when I have time . Getting rid of the carry handle/open sights adding my own flip ups as well a red dot , maybe a flashlight laser, clean up the internals a it just because, for the price I can put another 600$ into it and it will be a pretty darn good reliable lightweight gun. Mine is the da556 quad rail I think 18"barrel 1/9 twist ...I think . Mine was made in 2006.
Hope this helps.