There really is no way to compare the two. Aulani is a totally immersive experience. You can spend hours outside in the outdoor spa area and never want to leave. I loved it. I just went to Senses in January for a massage. It is a nice spa but just an average spa. They have a hot tub, but it is very, very small. There is also a steam room in the "wet" room area. You have to wear a bathing suit, even though the men and women are seperated. You are allowed to hang out as long as you wanted, but quite frankly, after my massage I didn't feel the need.
The services though were just as good as Aulani so you should have any issue with that...it is just the total spa experience that is very different.