It's hard to get all this music ideally recorded in one box, and I don't think it's ever been achieved. The playing is fine however, and interpretation is a subjective issue (after all, it's very easy to get used to a favourite recording). The recordings seem rather distant to me, as I have previously enjoyed many LSO live recordings, e.g. Sibelius & Dvorak symphonies, various Berlioz, etc.).
In summary, at the moment I feel that some of the symphonies fare better than others but a) I need to spend more time with them; and b) they still represent good value for money and you certainly shouldn't discount getting hold of them.