Our six year old boy started his piano lessons a year ago, and he's been (surprisingly) quite happy doing all his practices so far. We got him a pretty nice used keyboard ($40 on craigslist!) but it just doesn't sound or feel like piano. Lately his teacher has been mentioning how he has very weak touch during his lessons, probably because keyboard touch is much lighter than a real piano, and she's been recommending that we either rent or buy a piano.
We initially looked at two options: 1) buying a new, low-end piano (all made in China, ~$3000), or 2) buying a used, higher-end piano ($5k+, at least). We didn't particularly like the idea of buying a cheap piano, and we also learned that there are risks associated with buying a used piano. What we also learned is that moving a piano can be very expensive (minimum $1000+).
While browsing the web for an advice, we ran into someone suggesting a digital piano. Apparently advancements in DSP (digital signal processing) in the last decade have really improved the quality of simulated piano sound. So after some extensive research, we arrived at Casio PX-850 or Yamaha YDP-161.
Now, many folks out there felt that Yamaha digital pianos have a closer piano feel & sound, perhaps because Yamaha also makes real pianos. However, the reviews on PX-850 have been very high regarding its sound and feel (e.g it has 256 polyphony vs Yamaha's 128). To settle that debate, I took my son to a local piano store to try out the Yamaha, as well as the PX-830 (they didn't have PX-850); he preferred the Casio and I agree.
So, we ordered PX-850 and it got here in two (!!) days. It took about an hour to unpack and assemble; I was being extra careful and thorough, and I could probably put another one together in less than 20 min now. We were surprised how compact it is. It takes up less depth than our old keyboard.
Our son really loves his new piano and he now practices more than ever. The keys feel very much like real piano, as well as its touch and response. And finally, the best part... It sounds wonderful, just like a piano!
It's also great that you get THREE (3) year warranty (standard 1 year and you need to register with Casio), which is better than all other brands out there in its price range. You get the 1 year standard warranty out of box, and 2 more years on top of that when you register at Casio's website (http://www.onlineregister.com/casio/registration/)
BTW, this really is a brand-new model, announced only few month ago and just started shipping. Ours has mfg date of September 2012!
Overall we are very happy with the purchase. For all you parents out there, I highly recommend that you consider a nice digital piano like this one, over buying a cheap (but still $$) real piano. Let me know if you have any questions.
Disclosure: While I am not paid by anyone to write this review, I may be compensated if you purchase products through links on my blog.