The Donaldson ELF or Syntec is a great filter but it's expensive and it only makes financial sense if you are going to use all of it's capabilities. The specs I have is that its 98.7% efficient at 15 microns. That is about as good as it gets in the full flow world and I believe Amsoil uses that same media. That Wix example above, Beta2/20=6/20 is only 95% efficient at 20 microns, so it's considerably less efficient than the Donaldson. The Nominal Rating is useless: its only the size of particle the filter can catch 50% of on the first pass.
I will warn you that Wix is really getting screwy with their filter data and "homogenizing" many of them in a way that makes no sense. That XD filter is a prime example.
The only advantage to a larger filter is that more media allows for less pressure drop across the media (cold starts and cool starts plus high rpms) so the filter will bypass less. More media area also can carry more contaminants (though the efficiency will be dictated by the type of media, not how much there is of it). That allows you to run a longer interval but the extra capacity only pays you back if you use it. . I got some averages from some engineers at big fitler manufacturers and it was that the average passenger car filter is only 50% loaded at the end of a normal OEM oil change interval 7.5K). That number might go up for a tired a sooty diesel, but it's likely that the standard FL874 for our rigs is seldom fully loaded at the end of a 4-6K interval, or even close to it.
In general, synthetic media can be made more efficient with with less flow restriction. Good media flow is important with thick oil at cold starts and avoiding bypass (whereby some or all oil bypasses the filter) on cold or cool starts or high rpms. Synthetic media also has much more capacity to carry contaminants. Per square inch, most syn media can carry double the amount of contaminants that the average cellulose media. It often has nearly double the clean flow, per square inch. It can be hard to get that capacity spec sometimes but for one of my trucks, the premium cellulose media listed for the application can carry 18 grams of contaminants before the top level differential pressure is reached (filter blockage that leads to bypass). A premium syn media filter for he same application with nearly the same amount of media is rated for 31 grams...nearly double.
The main advantage to a high efficiency filter, and the advantage that can potentially return the extra investment, is the oil service life extension. Cleaner oil lasts longer in service because the additive package is less challenged and depletes more slowly. This applies strongly to the antioxidants and soot control additives.
Some will tout the lowering of wear and engine life extension benefits. That's more of a red herring in the financial sense. There is a range of oil cleanliness levels where the reduction in wear really levels off. In other words, the reduction in wear by going from a "normal" premium filter that's 95% at 20 microns (micron abbreviated "um") to one that is 98.7% @ 15 um, is not going to be huge and the extra expense will not be returned unless you crank on a lot of annual miles and run the engine for many years. The benefits curve is much steeper going from an old-dyle filter that was 95% @ 40 um to one that is 95% @ 20 um so that improvement pays off better.
The the bottom line here is that if you aren't going to significantly extend your oil change interval, a super premium filter like the Donaldson is not going to return your investment short of the next millennium. With that much syn media in a "footlong" filter, running a 4-6K OCI, I doubt the filter would even be carrying 10% of it's rated capacity.