Rainforest on Magic and Wonder are the same (even after refurb). The Magic/Wonder Rainforest has a small central court with heated tile loungers. Soothing music plays softly. A perfect place to read or take a nap. At the other side of the small central area there are some showers with different settings, like "Gentle Rain" "Thunderstorm" "Tropical Rainforest." These showers are for water therapy, and they often don't work terribly well. They are not enclosed, so they are not for showering.
Off the central court is a steam room that seats about 10, another steam room with menthol that seats about 2 (four if you are all good friends), and a sauna with tiled benches with a tiled angled back. The sauna is one of my favorite places on the ship.
There is no view of the ocean from the Magic/Wonder Rainforest.
On the Dream and Fantasy, there is a similar court with benches and with a couple of steamrooms. You can proceed through a glass wall to another room that has a glass wall facing the ocean. In this room you will find several heated tile loungers that face the ocean and a couple Jacuzzi tubs. Also, off of this room is a dry sauna that also has a view of the ocean, although through a smaller window. Note that this is all views of the ocean through windows or glass walls; it is not actually "open" to the ocean in the sense of breezes or being on a deck.
My wife and I enjoy the rainforest, but I think she puts it best: If we will be in a warm climate, she wants to lounge on the deck with the heat of the sun. If we will be in a cooler climate (like Alaska or the Pacific Northwest), she wants to lounge on the heated loungers in the Rainforest. Of course, on a cool or rainy day in the Bahamas or Caribbean, she wants to be in the rainforest.
Note that the men's locker room has a dry sauna that is complimentary and easily accessed. Also, I rarely see people in there. If you just want a sauna, use the one in the locker room. I don't know if the women's locker room has a sauna or not.
I think a one day pass for the rainforest is worth it. I won't usually buy a full cruise pass, because on port days I find I don't have time to go to the rainforest.
The sauna in the men's locker room, Disney Magic:
Heated tile loungers, central court of Rainforest, Disney Magic:
Tile mosaic, bench, drinking fountain on side of central court opposite the loungers, central court of Rainforest, Disney Magic:
Dry sauna with heated tile benches, Rainforest, Disney Magic:
Another view of dry sauna, Rainforest, Disney Magic:
A particularly steamy day in the mild steam room, Rainforest, Disney Magic: