If you get the polished ebony finish there's no indication that there MDF underneath. I made that decision way back in 2008 when I went looking.
If PE were not available I would not have bought a Clav. The high-end Arius is very nearly the same piano but in cheap clothing ... for a lot less money.
And with the P515, the clothing is more sparse, but this all black look is still better looking than the fake wood finish of an Arius.
