I think Seattle has more. More of everything. Certainly a lot more in terms of waterways and also more variety in terms of mountains.
That said, Portland sort of wins on proximity. Portland is so close to its best places. You can literally go mountain biking and trail running in the city. People do the Wildwood Trail (30 miles one way) without even leaving Portland! Sandy Ridge mountain biking is also less than an hour from town.
Heck, Mt. Hood is just an hour from your driveway. You can be on a glacier so fast... Hood lacks the variety of Washington's peaks but the fact is, it is right there!
Bottom line, you are in the Columbia Gorge, on Mt. Hood, in Forest Park, or on the Oregon Coast in no time. Proximity means a lot...
If you lived in Seattle, the "commute" to nature is longer (though the options in that area are amazing).