Solti summed up my view perfectly in his autobiography "I cannot see the point of playing the Hammerklavier on an old fortepiano which was considered inadequate even in the composer's day". Personally I find Beethoven on a fortepiano unlistenable and quite bonkers. The composer railed often enough about the inadequacy of the instruments he had at the time.
However, listening to Badura-Skoda, Brautigam, Staier or Cooper, quite a few seasoned musicians change their minds radically (without dismissing the modern piano, by all means).
One thing you have to keep in your mind, 33lp, is that the instruments used by the greatest Fortepiano players, mentioned above, are practically "restituted" in such a way that the limitations of the past are almost non-existing (or unnoticeable), giving at the same time colours and timbres that the modern piano cannot provide.
Finally, the different instruments from Walter, Graf or Erard (to mention some of the most well-known pianoforte makers), portray the exciting developments in sound and effects, where the modern pianos provide only the "final result".
Personally, I love the Fazioli (and some Steinways), as one of the most perfect examples of the development of the piano, but a great Erard can give a superb feeling of Schubert's or even Mendelssohn's music, while a Graf is so insightful for Beethoven.
Anyway, let's resort to the Latin wisdom and say: de gustibus et coloribus non est disputandum.
Good point. Remember, also, that Beethoven was deaf and his "piano" in a terrible state, apparently, and he used to drive his landladies mad by banging away ineffectively on this out of tune monster.
That's one reason why thirty six houses in Vienna can legitimately claim that Beethoven lived there...but not for long!