I have a desktop PC running Windows 10 and I recently purchased a Microsoft Surface Book Running Windows 10. My PC was upgraded to Windows 10 from 7 while the Surface Book comes installed with Windows 10 by default.
I can play the beta version on both computers using the same account. My issue is that I can gain achievements on my Surface Book, but I can't get them on my PC.
Even though Windows 10 has the achievements button, achievements have not been fully integrated into MCPE yet.