Which is the best Mac data recovery software?

I wouldn’t trust any of them. Have you already lost data? If you have shut your computer down. Every second you are writing over files you might want to recover. Use a different computer while you figure out what to do.

If you have one of the newer Macs, I would suggest getting either Time Capsule or an external and making good use of the Time Machine software to give you automated backups. That way, if something goes wrong, you can get your data back quickly and easily.