Beethoven - What Kind of Performer Was He?

The story of Beethoven, as one of the truly defining composers in  history, is known throughout the world, and continues to entrance the reader and listener.
However, how many of us come across information relating to his powers as a pianist?
Generally, what the reader inevitably finds is that this titan was a pianist of considerable gifts as a performer, especially of his own works, and, more specifically, in his powers in improvisation.As a matter of fact, many considered him as the most gifted improviser in Vienna, though barely out of his teens.
What may be of interest to the reader are views of his contemporaries, as applied to his performance abilities. For instance:
One contemporary wrote "In general, Beethoven played his own works very capriciously, though, at times his sensitivity to tempo change and melodic utterance was of great beauty."
Another stated that "his extemporizations were the most extraordinary things that one could hear. No artist I ever heard came at all near the height which Beethoven attained."
Another statement: "His playing was not technically perfect. He left many a note 'under the table' ".
The great teacher Czerny  reported of "his extraordinary extempore playing  was his strongest gift, as a performer."
Other impressions included such items as Beethoven's remarkable abilities  to bring out subordinate melodic lines in especially  his own music(who could know better what to bring out?).
Czerny also mentioned Beethoven's ability "in the rapidity of scale passages, trills, leaps etc., no one equaled this man."
Just a few of the written tidbits about Beethoven the Piano Player - thought you might like to know. There are many more observations about his performance abilities and weaknesses, and they can be found, if one should like to pursue the subject.