14K hammies have a soft blue color to them, they dont have as much PAR or the crispness of the P14K, and in all fairness AB20K has the lowest PAR of any of the options, not to mention that it is BLUE w/ a capital B. You really have to see the bulb to know if you'll like it, as it has no tint of white or anything just straight BLUE.
Another thing about the P14k's is that their nanometer peaks right where VHO Superactinics do, thus producing a true fluourescing effect not just blue light.
I use P14K's and i am now finally overdriving them on an HQI ballast, and lately things have been looking better even though the bulb is more than a yr old now. So until I find something that doesnt require 10000000W of act supplement Im sticking w/ P14K's. IMO they have a really pleasing color, and have the highest PAR of the blue bulbs, works for me.
BTW
Visual brightness doesnt equal better light, its the lux/lumens that matters not to mention there is also PUR (photosynthetic USABLE radiation) vs PAR (Photosynthetically AVAILABLE radiation), which blue is thought of to be the most penetrating in a natural reef environment.(water filters out all others after a number of meters, hence the blue color of the ocean)