As other reviewers have said, these symphonies are vastly underrated - the collection here is a must for classical lovers. The symphonies themselves are very different in feel, structure and mood, but are all excellent. The overtures too are very fine and again illustrate the variety and subtlety of Mendelssohn's orchestral composition.
Abbado and the London Phil are in great form, the sound and production are superb - never too near to be overbearing, but very clear and crisp. Buy it.