I have experimented with this a bit. My Anuenue Long neck Soprano sounds great a half step down, and my new Cordoba Concert sounds great a full step down. I am using Southcoast heavy high re entrant strings on the Cordoba, and martin Flourocarbons on the Anuenue. I can capo the concert at the second fret to get regular Uke tuning when i need it. I have since passed on the long neck to my daughter, and put it back up to C tuning. several songs work better for my voice in B flat tuning, which is one step down. Also, I like the tension better. Plus, my wife can capo her baritone at the third fret, and match my Concert tuning when that works or us. Loing necks, low tunings, and capos offer a lot of possibilities! Most of this I owe to info on Southcoast Ukes web site about strings and tunings, and some of his discussions here. I like the mellower sound of the B flat tuning for some of my classical transcriptions, but the bright C tuning is only a capo away!
take care,
Tom