Best speaker/system piano concerts

Any kind of music including piano can damage a speaker if the speaker is abused in some way. I wouldn't blame that on rock.

I play electric guitar frequently, putting distortion from various tube amps through guitar speakers in open back cabinets...I also play cleanly through the same rigs...these things should last for several decades as others I've owned have. I also have some old KLH Model 20s from a compact system I bought in 1970 or something (my first great sounding stereo) and they still sound great (relegated to a garage system). So there.

Underpowering any speaker can ruin it.  Any amp that isn't up to snuff can ruin .....  Bottom line is that it's hard to buy a used speaker.  Plenty of folks do and are happy, but I've heard so many horror stories about used speaker buys.  I have sold 7 pairs in my life and all three ProAc's need all new driver surrounds or speakers.  I wanted to make sure that I wasn't going to screw anyone, but plenty of folks do and will.

I would only purchase if I knew the person or maybe if it was local and I could go listen first, but even then, I'd shy away.  That's just me adn I really that, but often times folks end up with inferior amps in order to get 'better' speakers and they ruin them.  I agree that it's not just distorted rock. 

Underpowering any speaker can ruin it.

FWIW dept: the result being a fried tweeter.

When I got my Magnepan 1.7s almost five years ago, I was stunned by their realistic presentation of piano. Hearing piano through Maggies often cause me to turn my head in reaction to look at the piano that isn't there. I Googled to find some corroboration and I found this TAS review of the Magnepan 20.7, in which Jonathan Valin wrote:

... (Indeed, I don’t think there is another speaker that makes a well-recorded piano sound more like an actual piano than this Maggie. In part this is because a Maggie’s planar wavelaunch, as Dick Olsher once astutely noted, is similar to the planar wavelaunch of a concert grand, giving the presentation more of the size, volume, and dispersion of the actual thing. In the case of the 20.7 it is also because their bass is so extended, finely textured, and bloomy.)....

And that's pretty much what I concluded, too. The large panels approach or equal (depending on which model) the vibrating area of a piano soundboard, and radiates the sound in a pattern similar to that of a grand piano.
I know what concert pianos sound like. I worked for a high end piano store that carried Steinway, Boesendorfer, Schimmel, Falcone, Mason & Hamlin, Yamaha's concert line, and Seiler. The owners prepped Steinways and Boesendorfers for touring soloists such as Sviatoslov Richter and Victor Borge. In addition, my sister had music degrees from the Cincinnati Conservatory and USC. Her son competed in Russia's Tchaikowsky Piano Competition. My mom was church organist and pianist for about 20 years.
And piano music played through my Maggies create an involuntary response every time--I turn my head to look for the piano.