Welcome to Pianoworld. Based on the limited information in your post, you may not be ready to buy anything just yet.
I believe the C110A was a short-lived model with limited distribution. I have no first hand experience with that model under the Yamaha partnership, but the Pearl River upright pianos from that era ranged from underwhelming to poor in every way.
The Yamaha U1 is 35 years old. As a piano model, it does still have potential at its age, but a lot can still happen in 35 years. "Good condition" is far too vague to give approval.
I recommend learning more about pianos and about more brands before shopping.
Do you play? If you do, then step one is to see and try pianos. If you like it enough to buy it, have a qualified technician inspect it and report on its condition and service needs. Virtually 100% of "Good condition" used pianos have service needs even if there are no isssues of condition or wear before a new student can benefit from them. The amount of need ranges, but few private sellers have addressed a piano to have it well regulated, lubricated, voiced or regularly tuned.
If you do not play, then you need to take more time learning about what makes a piano good musically, good to learn on, and worth your money.