I updated this section since UNI Filter finally updated there web page I was able to add more to the debate on air filters, you decide what is better.
Air Filter Facts 
Open cell industrial grade filter foam represents the latest advance in air filtration
technology. This section describes how and why it works so well when compared to the
other three types also in common use. An optimum air filtering system is very
inexpensive insurance against untimely replacement of rings, valves, bearings, and
fouled spark plugs. These items represent very significant maintenance costs.
Additional benefits are provided by higher performance, better gas mileage, and lower
emission products. 
With an engine operating at the optimum air-fuel ration of 15 or 16 to 1 (air volume to
gasoline vapor volume), it normally means that 10,000 to 15,000 "gallons" of air are
sucked into the cylinders for every gallon of liquid gasoline in the tank. The exact
volume of air, of course, depends on the engine displacement, RPM, and miles per
gallon. For example, a 2800cc engine turning 2600 RPM at 55 MPH got 26 miles per
gallon, and used 23,000 gallons of air per gallon of gasoline in the tank. You can
imagine what 23,000 gallons of air and dust going into your engine every half hour
would do if you had no air filtration at all. 

Paper Filtration 
Pleated paper elements are used by more vehicles than any other type for these
reasons: 
1. They are the least expensive for the manufacturer to install as original equipment
from the factory. 
2. For the largest percentage of operating conditions (street and highway driving) they
perform well enough to satisfy the owner/driver at minimal acceptable levels. 
3. The elements are dry, easy to handle, and convenient to replace. 
4. Since they are "throw away" items (cannot be cleaned for reuse), they represent a
large and profitable part of the replacement market, while occupying our landfills. 
Paper filters are a stacked matting of fibers creating a random weave approximately
1/2mm thick, and rely on the "screening" effect to stop dirt particles. Airflow per square
inch is so poor that the paper must be pleated using many feet of material to make a
filter. All dirt or dust particles must be caught on the surface or not at all. Each time a
particle is caught, it stops up a hole. From the moment you start your engine, you have
a rapidly decreasing air flow rate. Paper also has two other big drawbacks for off-road
use. Any moisture reaching the element causes the fibers to swell, reducing airflow
even more. Another is the possibility of rupture. Paper is not a very strong material,
especially where it is creased to form each pleat. Intake manifold backfires, or cleaning
attempts with compressed air, usually rupture the paper leaving the filter ineffective. 

Pleated Gauze or Fabric Filtration K&N Filter? sounds like it
This is another screen type that is only 1mm thick. If the dirt is not stopped on the
surface, it is not stopped at all. These filters are sold on the pretence that they
maintain an oil curtain for the air to pass through, thereby catching all dirt particles. It is
impossible to maintain an oil curtain. The oil soaks the threads of the gauze or cloth,
but does not span the openings; otherwise, the air could not get through. The dirt
particles that do hit the threads have a good chance of being caught; the others simply
go through. The reason the filter does not look dirty on the inside is because the dirt
went into the engine. You can easily demonstrate this fact yourself by coating the
inside of your housing or carb throat with a thin layer of grease to trap some of the dirt
not caught by the filter Ñor you can place a foam filter inside the gauze element to
prove the same thing. 
The one advantage that this type of element has over paper is greatly reduced airflow
restriction; however, poor filtration efficiency is the price you pay. When dirt builds up,
filtering action improves, but now the airflow is poor like paper elements. 

Open Cell Filter Foam UNI filter? sounds like it
The development of this special foam represented a major advancement in air filtration
technology. Foam air filters now combine great airflow capability, huge dust holding
capacity, and very high filtration efficiency for extremely small particles. 
Fully reticulated (open pore) foam is a honeycomb of tiny, interlocking cells of uniform
size, which create an impossible journey for dirt particles since there are no
straight-through passageways. Each passageway (16 to 25mm long) is like hundreds
of very small centrifugal/oil bath filters connected one to another. In this way, foam
traps and holds the particles throughout the entire volume of foam. This is why they are
referred to as "full depth" filters in contrast to the paper or gauze elements, which are
screens, or "surface type" filters. The cell strands stop the dirt, while the oil film holds
the dirt like fly paper until removed for cleaning. 

Why is Foam Better? UNI filter? sounds like it
The principle of how a foam air filter works is simple:
"Open Cell" Polyurethane Foam is wetted with specially
developed filter oil. The "sticky" filter oil is suspended
in the path of the dirty air on the strands of the web-like
cell structure of the foam. This makes it impossible for
dirt to pass through the depth of the filter without
sticking to the strands. As the outer strands become
loaded with dirt particles, the wetted strands down
stream start trapping dirt, allowing the entire thickness
to be utilized. This prevents surface loading or air
restriction for 80% of the service life of the air filter
element. When the filter is sufficiently dirty, it can be
easily washed, re-oiled, and re-used.