Metchosin is right! I'd go for a good secondhand one with a steel or cast iron frame. A good quality wooden frame one will generally have a nice sweet tone and, if in good condition, might make a good buy. But because of possible warping, distortion, etc. it IS a risk. Hence, probably look for a metal framed model.

One thing I do not agree with in the article, having searched and played about 100 upright pianos finding one for our daughter, Hannah, is that a larger piano is a better piano. There are far more factors at play than size and it is like saying a large guitar is better than a small one. This is complete nonsense. After extensive research, the model we chose was a secondhand small sized Zimmerman (German) piano which gave the best balance betwen playability, sound, aesthetics and quality of action and parts. I bought from a dealer in this case, rather than privately, but nevertheless was able to negotiate and got a good deal (if we ever decide to upgrade to a more expensive piano, she will take back and give us an allowance equivalent to what we paid for the Zimmerman).

Regarding makes, I tend to prefer the "German" sound personally. We also tried some English, Belgian and French brands, modern, used and vintage. There were some truly beautiful looking French vintage pianos which would have made fabulous pieces of furniture but our daughter did not like the action. If you are in the USA, you will also have a wide variety of US brands to choose from.

My advice would be to try as many as possible, take the various factors mentioned above into account and choose the one that gives the best overall balance of desirable qualities in your price range.

Best regards,

mooman

P.S. Hannah started on a Roland synth, which she still uses for fun, but these do not generally have the necessary touch sensitivity and weighting of keys necessary for real progress. You can buy a digital piano with properly weighted and touch sensitive keys but for the high price you'd be better off with the real thing IMHO.