Most of the ukes in the shop I work at come stock with Aquilas but we're not dealers. When I heard that D'Addario worked with Aquila for the Nyltechs I assumed they would be very similar so I got some in for the store. I took home a soprano set to A-B it with my Flea (my only uke with Aquilas on it).
Not the same thing at all. Visually they're pretty close...I would say that the D'Addarios are a little more cream colored than the Aquilas. The D'Addarios also feel smoother than the Aquilas. Sonically, the D'Addarios are quite a bit more mellow than the Aquilas. Not a bad sound, just not what I was expecting. On my Flea, I prefer the Aquilas...unfortunately I don't have any spare sets.
So I'm going to order a set of soprano Aquilas soon and I'll do a sound comparison between the two sets of strings once I get them.