Marin is a beast, no other way to describe it. It's similar in length and average gradient to hills like Mount Tom and Kingsley Hill (though it's shorter and steeper than either). But what the gradient map doesn't tell you is that there are many, many cross streets running across the hill, which are perfectly flat. This means that while you do get momentary pauses (or more than that if you can't manage to keep going and choose to take a couple minute break), it completely screws up your rhythm. Add to that, there's considerable traffic on the road. And what really makes it tough is that the final sections, which are much harder than they appear on the gradient map (view the segments listed below), are off-the-charts difficult. Since the bottom is very hard, there's no chance that you'll have momentum or be able to maintain momentum when you hit the sections of >30% that come at the top. Zigzagging is an option, but the aforementioned traffic means that you may get burned if you opt to try that route. My sense is that it is harder than either hill mentioned previously, but then again, there's always a learning curve to figuring out the best way to tackle a hill like this, so maybe with more practice it could be a bit easier.
Marin Ave is located in California. It is 1184.8 meters long with an average gradient of 17% and a maximum gradient of 26%. Find similar hills.