If you live in North America, you have the opportunity to purchase a quality used piano for $200-$1000. None of the brands mentioned are likely to be in this price range, because they have sales support. The orphan brands of the great US factories that were closed and sold off in the 80's, those are the great console and studio pianos that I play and respect. Modern sounding consoles started about 1939, and the US console factories closed in the 80's.
In my location, southern Indiana, great used pianos are going to the dump or the flea market every day. These are fifties and sixties quality brands that were bought and neglected by their owners, except for some furniture polish. They will typically be way out of tune, because it hasn't been done in forty years.
Brands I have found to be good pianos if made before 1990: Steinway (not school surplus, these are beat to death) Sohmer, Baldwin, Hamilton by Baldwin, Wurlitzer, Mason & Hamlin, Chickering, Somewhat less pleasing in tone, Everett, Goodall, Yamaha.
For boys that can play fast, don't buy a piano shorter than 39" tall. Baldwin and mason & Hamlin make a nice sounding 36" piano, with the Baldwin the faster of the two, but not as fast as my Sohmer.
If your boys are likely to get fairly advanced, look for a model that has a middle pedal that does bass only sustain. There are a couple of pieces I play (like Pictures at an Exhibition) that one can make an approximation of a grand's middle pedal with a bass only sustain. The Yamaha consoles I've played, they had middle pedel a sound dampener, which I find fairly useless. My 82 Sohmer 39 has middle pedal as bass sustain.
Many great pianos in my market go for $100-500 on Craigslist, usually right before the carpet installer comes, or the SuperBowl or March Madness requires the space for a big TV. OTOH, many mediocre pianos that were locally made , sell at $1000-1500 because somebody's father worked there.
The piano I like best now is a 1960's Baldwin Acrosonic 40" I play at a downtown church for their charity dinner some Saturdays. Acrosonic is about the loudest brightest console I have ever heard, with Baldwin making the Hamilton brand for the customers that preferred a duller sound.
To determine if a used wood piano is worthy of consideration, first do a chromatic run on every note. Keys that stick at this price are not worth considering unless the cause is straps missing, which can be replaced in one minute with polyester fabric. Play very softly and see if the touch is even. Oddly many $50 prewar uprights pass this test better than lower price import pianos from the nineties and later (I'm thinking of a 90's Wurlitzer I played recently, that was very uneven when played softly. I've played a seventies Wurlitzer that had very even touch). PLay it loudly and see if any keys double strike. Pick a key and using two hands, strike it repeatedly as fast as possible. Can you outrun the action (bad), or does it strike every time as fast as you can go?
Now open the front. Look to see the hammers are not scooped back in the middle, the way school and conservatory pianos get. That kind of continuous hammering beats down felts, whereas home use pianos the felt tends to spring back. Make sure there is no mouse eaten felt. Make sure the hammer shafts are all straight, and none of the joints in the action are coming unglued. Look at the straps now, the leather ones tend to come undone in 60 or more years, but polyester shirt material is quite superior. Are all the strings there and are any visibly spliced? Usually near the top.
Look at the soundboard from the back that it is not visibly cracked. Listen to the tone, however badly it is out of tune, is it pleasing on bass notes, two string notes, three string notes, the top octave? This is where I've come to hate Yamaha, their bass notes are so boring. My Mother's 49 Everett had a funny tone mismatch between the two string and three string notes. Is there any buzzing? You don't want that. Do the pedals work evenly? Two imports I've played recently a Yamaha and a Schein, had some weird sound damper middle pedal instead of a lower half sustain, which didn't even work on the Schein. I use the lower half damper pedal (middle pedal) on my 1982 Sohmer for some pieces I play.
At this point I'm ready to buy or walk away, but you are welcome to involve a proffessional if you wish. Note many will be tempted to bad mouth anything you find because they can sell you something "better".
If you buy a superior used piano from a flea market that the vendor lists on craigslist, somebody will have bought the piano at the above price, tuned it, and perhaps fixed a few things. the tuning makes them worth more, but take a tuning fork and make sure they are up to pitch already. (440 for post WWII pianos, A432 for pianos from the twenties or earlier). If not, you'll have to pay more for tuning up to pitch, and you don't know how tight the holes are. These flea market pianos run $600-$800 in my area, with free delivery.
One advantage of a used piano with boys, you don't have to worry about the finish or muddy tennis shoes. My 41 Steinway 40 has several veneer dings and knocks from children, that is how I got it after the professional restorer "first responder" rejected it. A used piano is basically worth $200, with some of the lesser brands not mentioned getting more because the finish is perfect because noone ever played it.
Anyway have fun shopping. In this town, new pianos are Yamahas or Boston's, not much choice.
Topic: Need quality upright for twin 13 year old boys