I do own concert Ortega RU11. I bought it about 3-4 years back - was a replacement for my first, "noname" 30 euro junk ukulele.
Very happy with it - though I cannot compare with other brands/models. I switched about 4 sets of strings on it in total over the years, playing with low to medium frequency/intensity... currently using Aquilla reds. It holds tuning nicely, i need to re-tune it tiny bit about once every other month. Nice sound and tone IMHO.
I managed to bit off a tiny bit - about 0.5x0.2cm of wood/shellac laquer layer on the side - a clumsy unintended bash to a hard wood table two years back, and it still works solid & strong, only an appearance "defect".
Currently I am looking for some tenor model, and am considering Ortega again...