Your quilt top looks great! Very colorful!
You can also combine hand quilting and machine quilting, if you like. You could do the stiching in the ditch along the major lines, then add the hearts by hand afterwards.
If you're going to do all by hand, I would recommend stiching 1/4" inside the major squares, rather than stitch in the ditch. SITD is very hard by hand, as you encounter so many layers at some points. I do the 1/4" inside the sewn lines. I mark them with masking tape, as I cannot hand stitch a straight line without that guide.
Looking forward to seeing your progress!