One of the members of our Piano Buddies group has a newish "Cristofori" baby grand piano around 5', (maybe 5'3"?). However, as with many older piano brands/names, it is made in China with a Cristofori decal on the fallboard.
The piano looks nice, and sounds and plays okay, and the owner has it tuned and serviced regularly by a qualified piano tech. But I would not call it mellow sounding, and I know what mellow sounds like.
I'm not saying all Chinese made pianos sound the same, but the ones I've played sound and play similar, which does not mean bad; just similar. I'm sure there are some more mellow sounding ones out there, and the Ritmuler brand may be one of those brands. I don't remember ever playing a Pearl River, but I like the sound of the name itself; I may have played one, and it just don't remember it.
Also, FWIW, I'm in the camp that believes all pianos sound and play slightly different, even among the same brands and sizes.
Also, (part II:-) I'm with Carey, although a newer/nicer/better piano will inspire and encourage you to play more, I'm not so sure the piano alone will take you to a higher level of playing, without the hard work and practice involved in getting there; although a newer/nicer/better piano will likely be more enjoyable as you make your journey toward piano virtuosoism.
Wishing you all the best with your piano search!