As for Steinway uprights, I haven't had any personal experience with them. However, I have heard (I believe it was from a book somewhere) that their uprights are not all that great. As for Young Chang, I only looked at grands, and I don't remember how it was.
I have had only good experience with Kawai's that have been placed in homes. I have played a great many in music schools, and they just don't hold up like Steinways. I was very pleased with their hold up, tone, and action when it was owned for personal use. However, if I remember correctly, they are extremely pricey. Also, Yamahas typically run very pricey as well.
I would look into a brand called Petrof. I own an upright, and I borrowed a grand from a friend for about six months, and I was extremely pleased by both. The color (especially in the grand) was remarkable. They are also a little on the cheap side, since the Czech Republic subsidizes their export (although I have heard that this will not last much longer).
How long was this music festival that those pianos were in? If it was a couple weeks, that should be fine for the piano. However, I would stay away from pianos that are owned by music schools. For instance, Interlochen School of the Arts sells their Kawai's periodically, and you never know how well they are maintained there. They may be somewhat rebuffed for sale, but who knows what their long-term care was like?
Mike