I use a Dri Ducks suit ( 10 ounces ) and a Golite umbrella ( 6 ounces ).
For heavy rain I'm pretty much sold on the umbrella idea. Believe it or not, I'm still hiking in and out of our homestead every day, the access road is on a steep north facing slope that holds ice and snow sometimes till early May!
My golite umbrella stays in my day pack that I take to work every day, and is very useful for warding off rain on the short 1/2 mile hike home or down to the car.
It gets used allot in the spring!
Out on the trail all day long, I do prefer to have the 'brella and a breathable rain suit. The suit keeps my legs and pants ( if I'm wearing any )dry and is useful for wind protection and is very warm to sleep in too, so it is a multi purpose item.
It keeps me dry when I have to set the umbrella down to do stuff.
The total weight of the combo of about a pound isn't excessive for me, I get allot of rain!
To keep my pack contents dry, I made a number of very light silnylon stuff sacks, and of course I use a few zip lock bags as well. Good enough.
Now, about umbrellas -
I reckon umbrellas are kinda like guns -
If yer gonna go through the hassle of carrying one, make sure the dang thing is big enough to get the job done right!
The tiny six ounce Golite umbrella is useful to a point but it really is simply too small. I've been looking for a bigger replacement. We have a few other umbrellas that we use and our favorite is a big golf umbrella. To heavy for backpacking, but it is like carrying a tent along with you!