Nothing but "seat of the pants", IMO, and "looks good to me".
Now how much more do you want?
Really though about the only thing that holds true is: more watts means more light. Piaa has more watts.
The bluish type bulbs are not as bright. I tried Solaris & Hyper white and they arnt close to PIAA. All the bluish types fade out or dissapear or something on a rainy night so that you think you have your lights off. PIAA's dont do that....
I've probably spent $100 trying different lights and the PIAA's are by far the best.
Nothing you can do about beam patterns and distance except spend a night alligning your lights and then buy aftermarket fog &/or driving lights to fill in the dark spots.
Hope this helps....
