Yes, the Employee Free Choice Act strengthen worker's rights, because it allows workers to choose whether or not they see the value of a union. This makes the companies more responsive to individual demands, rather than waiting for the union to make a demand. This improves options and ultimately working conditions for the workers.
Yes, the EFCA strengthens worker's rights. It allows workers to form a group of people who all work toward common goals within the workforce so that all are treated equally and are not treated unfairly due to injury or inability to work at the level others do. They also allow for employers to not discriminate against those who might join a union.