guan sheng versus synta

Does anyone know the difference if any between the 10" synta mirror or the 10" guan sheng... Is there any??

I just keep hearing reference to them but nothing specific as far as differences..

Example Orion switched to Synta on their Orion Xt's but prior to that they were using Guan Sheng..

Any advantage to one over the other??

Thanks

Mark Visser