I migrated from Grin++ to Grim wallet a while back. You can plug your seed from Grin++ into Grim and it carries everything over, even had my Tx history. Quite seamless and quick process. Grim is frequently updated, has active developer. Grim - cross-platform GUI for Grin - #101 by ardocrat
Do wish Grim had ability to copy wallet balance. Grin++ eventually had this feature implemented upon request by David, which has been a standard feature on all other wallets for other projects from my XP.