One major disadvantage to the ULA's filter is that it's not field cleanable.
Funny, I've cleaned this filter in the field three times, two of them just for practice.
I haven't really timed the filtering speed of the ULA Amigo Pro and I really don't care, because while it's filtering I'm doing something else, like resting or cooking or admiring the scenery or some such. I don't go out backpacking to indulge in speed; there's too much of that going on in "civilization." I'm more interested in weight, price and effectiveness. If I want speed, I'll get a Steripen or return to using a pump filter.
I'm only familiar with the Hiker Filter element. I know, having used one on several trips, that it isn't field cleanable, especially to the 80% rate of the Hollow Fiber filter. My understanding is that the Hiker Pro cartridge simply has a fine mesh screen that surrounds the same filter element that has always been the Hiker. This is simply an internal prefilter and the pores of the screen aren't small enough to remove the microbes which pass through to the main element. My feeling is that you may be able to clean the stuff that can be seen in the water (algae, dirt, etc.), but the stuff that can't be seen is slowly clogging the Hiker Pro's main element.
The Hollow Fiber is a non-absorbing material (unlike the paper filter of the Hiker and Hiker Pro) that releases very easily the microbes that normally clog a filter. In the case of the Miniworks EX, the user can simply remove layers of ceramic. With the Sweetwater, the user removes layers of the fiber matrix from the inside (special brush) but some of the gunk that is absorbed can't be removed. However, with the Hiker Pro, the only thing that can be done is to either clean the mesh screen or replace the screen (I've inspected it very thoroughly and feel confident that this is the case). You simply can't clean the main filter element effectively. Although there is a claim that backflushing helps, I've never noticed it working for me.
I'm not here to promote that the Hiker Pro or Hiker are bad. I do think the fact that they aren't as field maintainable as other filters (as is the case with the Hiker Pro) is a disadvantage, but they have many advantages. I've used them for several years and have always had good experiences. However, based on my experience, I have never successfully been able to clean a filter element in the field or at home. In some cases I've only been able to filter 20 gallons from my Hiker due to blue-green algae in the high Uintah Lakes.
Hollow Fiber is fully cleanable and will improve the performance of the filter almost to what it was when you first bought it. It's not as good as the Miniworks, but far superior than any other filter currently available.
In terms of the speed, the reason why gravity fed filters aren't that widely accepted is because of the weight and speed. I believe that if the user would realize that they can get water as fast from their gravity fed filter as from a pump, then more people would be interested in the gravity fed system. I agree that we are in way to big of a rush in our daily lives and to get out in the backcountry and slow down is highly desirable. That is a huge reason why I go out. Unfortunately sometimes I don't think ahead and seem to forget about water until I need it. With the AutoFlow, this isn't a problem. With other gravity fed filters, I would wait upwards of an hour or more (not the case with the Amigo Pro). The best thing is, even when the water is ready to consume after only 4 minutes, I can still lay around and veg until I'm ready to use it.