I think it's called "decision paralysis" -- the concept that too many choices can be a bad thing. Having to decide between too many options can be paralyzing. Anyway, I'm starting to feel that way in regards to choosing a new air filter for stage 1 on my '07 FLSTN. The bike already has Reinhardt slip-ons, and I'm planning on installing a XIED.

OTHER THAN APPEARANCE, is there any real difference in the multiple HF air filter options?

 

The way I understand it is, no, not really.
A free flowing air cleaner just gives a less restrictive path than the stocker, so basically your primary choice here is looks...

 

 

For a minute I thought HF meant Harbor Freight .... Thank God it isn't!

 

It's my understanding that almost all high flow A/C's flow more air than your engine can use so like said before it's basically the "look" that you choose.

I chose a DK Custom Outlaw A/C for my 06' Deluxe due to the old school look and the breather bolts. Many other aftermarket A/Cs route crankcase air thru the A/C and back into the engine.
From their website "The EPA has required Harley to route hot, dirty, oily crankcase air back into the air cleaner compromising the performance of your engine. This vents it without compromising the performance or longevity of your motor." http://www.dkcustomproducts.com/Twin...ystems_c78.htm

I've been very happy with it. Hope this helps Good Luck!

 

For the most part, all High Flow, Stage 1 air cleaners provide the same performance gains. I personally like the Arlen Ness Big Sucker for it simple design.