What's your hammer wrapped in? - Contemporary versus older pianos

As I contemplate the acquisition of my friend's mid-ninenteenth-century Pleyel  grand piano, and have been reading about Pleyels and the piano improvements of the mid-nineteenth century (metal frame, overstrung design, duplex scale, and hammer coverings, etc.) which paved the way for the next 150 years, I found these videos and documents which those of you who enjoy the Pleyel, Erard, and other antique instruments may like.  Of note, as I am playing the antique pianos in Pianoteq, I wondered why they have such a distinct, almost warbling sound.  From what I read and see in these documents and videos, much has to do with hammer-coverings (although the straight-strung older grands without Steinway's overstrung innovations do have a 'cleaner', less rich sound).

https://drive.google.com/file/d/0B8EJs_...9iV1E/view  This is an article in PDF format on hammer coverings in Chopin's time, going from leather to wool felt.  While Cristobaldi may have brought us from the harpischord to the piano in the late 1700s, Pape with his felt has defined the sound of the piano for > 150 years.

https://www.youtube.com/watch?v=VMgT1xeOoXA   This a video presentation of the technical details that created the mid-nineteenth century Romantic piano sound

https://www.youtube.com/watch?v=d8GqpKhaMo4   This is a comparison video between two mid-nineteenth century French designers: Pleyel and Erard.  The Pleyel, Chopin's preference, has a lighter and more delicate sound, while the Erard is more dramatic and darker.  While the commenters on the video criticize the performer for playing different music on each, the character is fairly clear.  It appears that the public through history prefers the sound of the Erard, as it embodies the powerful traits that shape the sound of our contemporary pianos, rather than the more delicate Pleyel (even twentieth century Pleyels sound more like mid-nineteenth-century Erards!).