First of all, welcome to the forums!
I've got a KoAloha Superconcert (concert body and tenor neck) from 2007 and a well played Kamaka Concert from 1997 (so very well played that finish on the first few frets of the fretboard have worn off...we're past the fretboard grime stage) My KoAloha is strung with Worth Browns, and my Kamaka is strung with Worth Clears. So already, I cannot make a direct comparison between the two, because of the models, the ages, and the strings.
However, as much as I love KoAloha, my honest opinion is that my Kamaka concert is the better sounding instrument. That could probably be b/c it has aged very nicely, especially with lots of love and play from the previous owner, and b/c I've heard that Worth Clears are better sounding than Browns. So again, this is not a direct comparison, sort of apples to oranges, but I can say that my Kamaka white label concert is an amazing instrument.
I don't know how much they've changed the Kamaka Concert in the current form, but really, as everyone has said, you can't go wrong with either. I also love my KoAloha.
And you know what the best part is? Both my Kamaka concert and KoAloha Concert were factory seconds, and they still rock.