Your model looks perfectly Symmetrical to me!

Also when i was experimenting, i found that bets results are achieved when you turn off Vertex normals. Sometimes this can create black areas on your mesh, where the normals are messed up!

So, like i said i don't see a difference in your mesh, So maybe thats why can't see any results.

Other than that i guess you could make sure your transferring over the right axis. Maybe your model is mirrored over the z Axis??

I'll keep playing with setting to see what i get in Maya, but like i said it's working fine for me.

Try creating a Sphere and messing up one side, and try the Transfer Attributes on that. If it works then you know it's the model thats having the problem, and vis versa.

Good luck