The best I've seen so far. Right on the Pacific, you can feel the rocks shuddering under the violence of the surf as you lay in your perfect peaceful pool gazing up at the moonlit steaming waterfall. Go in the winter at low tide, I've heard the springs are overrun by tourists in the summer (dozens lined up to get in), and high tide covers the most comfortable pools. I went on January 3 this year, camped over a night and had the entire place to myself from around 6pm til 8am.
From Tofino on Vancouver Island, catch a boat or plane to the cove. I paid $40 for the 2-hour boat ride there and we saw orcas, three adults and a baby, on the way! I flew back to Tofino from the Cove in a little float-plane, which cost $60 for the 15-minute flight and extraordinary view. You can do a daytrip, though you'll be kicking yourself for agreeing to leave so soon. Better to camp, but bring supplies for an extra day or two as transportation in and out of the cove becomes impossible in bad weather. There's a campground open in the summer near the dock, but in the winter when no one's around you can get away with putting up your tent in the trees right by the springs. I found a little clearing within 50 feet of the sea on three sides! There's also a Bed & Breakfast Boat called the Innchanter at the dock that you can lodge at. From the dock, there's a two-kilometer boardwalk through old-growth forest to the actual springs. (That's just over a mile.) There is a little changing hut at the springs.
The water is very hot above the waterfall. I could hardly stand to be in it. Below the waterfall the temperature is perfect. The air temperature was below freezing when I was there but I was quite content for hours in my pool wearing nothing but a toque. (Beanie, for you Americans...)
There's a sign up that bathing suits are required, which makes sense when dozens of tourists are squeezing in cheek to jowl. Better bring a suit for daytime soaking.