Sir Charles Mackerras is a great conductor and scholar. He was among the pioneers in what is now called "historically informed performance", but has not really gone so far as to embrace original instruments or "period performance practice".
Mackerras' recordings of Handel and Mozart are well known; in the past several years, he has expanded his recorded repertoire to include Beethoven, Schubert, Mahler, and now Brahms. He also has a specialty in music of Czech composers such as Dvorak and Janacek. This recording, like so many others of this great and relatively little-known conductor, is one of the best available of these works. (Believe it or not, it is hard to think of a single recording by Mackerras that is not among the best; his Handel Messiah from the late '60s is still a great choice)
The Brahms serenades are "lighter" than the symphonies, but these performances are "lighter" yet, in that the orchestral clarity characteristic of the "period performance" style is ideal for these beautiful works, and Telarc's recording provides even more clarity. Anyone who thinks Brahms is ponderous or "thick" should try these works in these performances. After hearing this CD, I am determined to go get Mackerras' recordings of the Brahms symphonies.
You will love this music; and do yourself a favor and go get Mackerras'recordings of the Dvorak Slavonic Dances too!