As Shubert commented earlier, excellent performance.
Original orchestral instruments sound with a different sonority (timbre) than modern instruments. Generally speaking they were softer textured. This often means that certain compositional musical detail can potentially be heard more clearly. May sound counterintuitive, but the more powerful sound of modern instruments en masse can obscure subtle detail that the composer intended to be more clearly heard. The argument against period instruments is that some music lacks that sense of power. Ultimately, it is the interpretative skills of the conductor and players that determines wether its is a good performance of not. The use of period instruments, by itself, will never make up for mediocre playing or conducting.
One of the driving forces of the period instrument movement is the stated goal of observing very strictly the composer’s indications in the score. Beethoven included specific metronome markings in his scores so that there would be no ambiguity as to what the tempo of the music should be at various points in the piece. In modern times, the trend has been to perform the music faster than is indicated in the score. This is probably the main reason that the “repeat” indications are not observed. It is fairly common practice for modern conductors/orchestras to not observe the indicated repeats of certain sections in the “written score”.
Just as in Jazz there is a general playing style that is typical of a particular period in the music. This is in part a product of the inherent sound of the instruments available at the time as well as accepted performance practices at the time. Not sure what the author of your article means by “demanding playing style of the time”. It is demanding because it is not how most modern players approach playing that music.
I like the “period instruments” approach and its attempt to get as close as possible to the sound that the composer wanted...as one valid approach. However, there are a couple of things that make me a (little) bit of a skeptic. The case of Beethoven is particularly interesting....he was deaf by the time he wrote his 9th. It is entirely possible that the sounds that Ludwig heard coming from the orchestra in his head were quite a bit different than the sounds of instruments at the time were able to produce. Secondly, composers were often frustrated by the limitations of early instruments.
Great performance with some unique qualities, but don’t throw out you Kleiber recordings yet. In most great scores is built in the potential for different and still valid interpretations.
