To be fair, I had the same problem and the first boot didn’t succeed.
I had to rescue the system, switch the “boot” flag to the btrfs partition (it was still on the Win* one), boot the system somehow, then reinstall GRUB2 from inside the running system. No problem after that, even with hibernate or multiboot (there is a workaround script installed by default.
Anyway, I agree with gogalthorp: on a laptop it seems not worth the hassle…