Both Freeform (or Tumbled) and natural crystals are excellent healers and great protectors. They may provide different forms of energy, but they are both effective.
Towers have a bit of a different story. The pointed pillar of the Obelisk symbolizes the journey of the spirit from material “earthly” world to the subtle energies of what we call the etheric field. It’s said that “the pillars of the obelisk support the heavens, humankind’s highest aspiration.” The Obelisk gives one the courage to be open to different, sometimes far-reaching points of view. The Tower shape supports the movement inward by way of creative thinking and introspection, allowing one to reflect patiently.
Bringing a crystal of either formation type into a room will imbue the space with a stronger, more focused source of that crystal's energy.