Welcome to our forum.
To me, an important consideration is how the tub is insulated. If the tub is a "full foam" tub, the blower will be pulling air from outside of the cabinet, therefore (in the cooler months/climates) you WILL have cold air coming in, which is uncomfortable, and cools the water. If you have a "thermal pane" insulated tub the air comes from inside the cabinet... therefore it won't cool the water, and wont be as uncomfortable. Granted, the air inside the cabinet is not as hot as the water itself, but 90 degrees is a lot better than 15 degrees.
I agree with Tony that the Lavender is the most powerful.
My question now is this: Is this not also true for the air that is added to the regular jets?