I have the opportunity to compare the 2 kits (a friend owns the Anigrand, and I have the RC).
Despite the RC is "only" 25/30 cm longer (~100cm vs ~70cm ), it looks at least 2 times bigger.
About the accuracy, it depends to which Stardestroyer is prefered : ANH or ESB
For the ANH one : the Ani is closer, but not stricly accurate (sort of mix between ESB and ANH)
For the ESB SD : the RC is just perfect ! while the Ani have 2 noticable inaccuracies : a nose too sharp (easy to correct I think) and the 2 parallel strips on each side of the upper shell, all along the edge of the trench (a nightmare to correct).
Quality if the master : Anigrand first. It was certainly made on computer-controlled machines : engraved panel lines are completely straight, etc. It looks a mass product item. Its even too perfect, as, to my taste, lacks the personality of a craft item. The parts breakdown is also better designed, it really looks easier to build.
Quality of molding : Ani first again, and by far : it looks like an injection kit, without any bubble, whereas RC have some. The RC needs lot's of cleaning on the parts.
This comparison was done on the un-buildt kits, not on the final results (the 2 are still in their boxes !)
Sorry, we didn't shoot any photo that day ! (maybe another time)