I tend to favor period instrument recordings of early music, but had never taken note of the significant sonic differences between modern pianos and those which 19th century composers would have known. This article highlights those differences, and offers some interesting comparison audio clips.
On old pianos
05
Mar
Diakrisis 
Peter
March 8, 2010 at 6:10 pm
Interesting. (though I think the earliest clips–Mozart and Beethoven-era pianos–sounded mostly tinny, a bit too bright and out of tune to my ear) The columnist makes a fine point in favor of sticking with the good solid European artisan pianos though. :) I’ve never been a fan of Steinway–the default action is way too heavy.