I made the choice to go to the Willow Stream after feeling like I was on a conveyer belt at The Grand Waliea spa a year ago. This indeed was a better fit for me. The newly redone spa is impressive and there are no tired broken tiles and leaky faucets like at the GW. My therapist was right on time to pick me up in the lounge, and the stone massage was just dreamy. Lorraine is a magician.
There are a number of "experience" showers, but i didn't get the sense that there was a scent of any kind (which I expected, similar to the GW) but rather a change in lighting and drip pattern. You have the option of dialing the temperature up or down to your liking ... they are open view with a panel of glass however, which is always funky. There is a "mud bar" which amounts to you selecting a cup of mud and applying it prior to sitting in the steam room. The private showers include all that you need to prep for the day after your treatment(s).
I found the reservation process to be easy and every interaction I had with staff was pleasant. I would not hesitate to come here again and if you prefer a more intimate environment this is a great option in Wailea.