The O2 Rain gear is generally considered more durable than the DriDucks.
I have an O2 Rain Gear top and bottom, but have yet to use it in the rain.
I have seen it in action with my friend, Jeremy, on a trip we took together with 1 day of rain.
O2 Rain Gear works, but I would hate to see how "less" durable the DriDucks are, given how easily the O2 Rain Gear can be damaged.
Sitting on rocks or a fallen tree can wear down the surface layer of the O2 Rain gear.
Long term use over multiple days, I would expect that duct tape patching would be required.
I am currently looking for a more durable and light weight replacement.
I think that the O2 Rain Gear is fine for the Sierra afternoon showers, maybe others can tell if it holds up well in constant rain, like the Pacific North West.
The positive about both of these is that they are cheap, light, and are supposed to be breathable.
Anyway, hope that this helps.