I originally bought the Hiker Pro filter. It worked fine but I really didn't like having to position myself in sometimes precarious positions to pump water. It also seems that everytime you push down on the plunger, the pickup wants to jerk into some debris.
I bought the ULA Amigo Pro and I've used it twice so far. One time was from a tiny creek with only a trickle of water. I'm sure pumping from it would have been a little difficult but I found a spot where the water was trickling over a waterfall. It was easy to fill the bag of the Amigo Pro.
As far as weight, I feel it is lighter than chlorine dioxide drops and here's why. The Amigo weighs eight ounces with stuff sack. Chlorine dioxide I think weighs 3 ounces (and let's say that you prefilter with a bandana that you're already carrying). At a water stop with the Amigo, I can instantly drink and fill up on water and carry less. With the drops you have to wait I think 20 minutes so you're probably going to be carrying that water for a while before you drink it. I think they are pretty even in weight when you consider this.
Then there is the benefit over the drops of filtering out debris and improving the taste.
Just my thoughts,