I am now listening to the fourth cd and i like the set for sure.
From what i read i understood there doesn't exist a totally essential complete set as a whole. If you want cream on your listening experience you have to listen to several seperate recordings of his Symphony's.
What i like about this set is that it has a feeling of distance about it but at some spots also a feeling of warmth. I expect it to be played like this. Barbirolli has the same Zodiac Sign as Sibelius. So puristic material i would say... Sometimes slowly revealing it's beauty, and often powerfull in the last movement of the symphony.
Sibelius himself liked the way Barbirolli conducted his works so that says a lot to.