In spite of Mahler's disapproval, his eighth symphony is forever tagged as the "Symphony of a Thousand" because of the immense choirs which perform it. Last night's performance, the first night of the 2010 Proms, made a magnificent sight, with red and purple-robed boy choristers below the great Royal Albert Hall organ behind an extended BBC Symphony Orchestra, flanked by hundreds of singers from choirs from London to Australia. Perhaps a shade short of the 1,015 musicians said to have performed at its 1910 première, but a splendid sight in the vast, bowl-like setting of the Royal Albert Hall.

The music is monumental in conception; it seems that Mahler intended it as a parting gift to the world. The huge personnel count means it can't be performed all that often, so it's a fitting piece to be performed on this vast stage in this year, the 100th anniversary of its première and the 150th of Mahler's birth. In contrast to some of Mahler's earlier symphonies which mix light with darkness and the sacred with the profane, this is a thoroughly spiritual work, and the intended theme of this legacy is clear: Mahler is depicting holy rapture, the joy of the soul drawn up into the divine. And the composer doesn't waste time in getting the message across: the symphony opens with a thunderous organ chord and choral tutti with the words "Veni, creator spiritus" (Come, Creator Spirit) melding into a joyous brass fanfare. The symphony's first movement, lasting around 25 minutes, is an extensive set of variations on this Latin hymn, in which the different soloists and choirs pass the melodies around to each other. There are innumerable changes of pace, dynamics and orchestration, but that single mood of the elevation of the spirit to a higher plane prevails throughout to the movement's massive conclusion.

The second movement is a complete change in style from the contrapuntal, church-music feel of the first. We hear something unique in Mahler's output: a sort of mini-opera based on the last scene of Goethe's Faust, in which Faust's spirit has overcome the best efforts of Mephistopheles and is assumed into heaven. After a long instrumental overture which both anticipates the themes in the rest of the movement and quotes some of those from the first, we are treated to a soundscape in which the eight soloists take on characters from the bible and Faust's past and the choirs represent different groups of angels. The music is highly theatrical, from the depiction of Goethe's wild nature with its rocks, forests and waves through to the final "chorus mysticus" in which the spirit is drawn towards the "Eternal-Feminine".

While the audience received last night's performance with enthusiasm, I have to confess to some disappointment. The choral singing was certainly imposing and accurate, and of course, it's wonderful to hear such massed forces in such a setting. But while I heard plenty of power and musical intricacy, I didn't get the sense of rapture that is so clearly the intent of the music. Partly, this was down to the soloists. Singing to a space the size of the Albert Hall in competition with several hundred other musicians is a tough ask: you need a huge voice, particularly in the operatic second half. Stephanie Blythe was outstanding, singing with the power and authority needed to command the hall; the other soloists may have been perfectly musical, but they didn't command the listener's attention in the same way. And while conductor Jiři Bělohlávek certainly kept everything moving briskly, I didn't get much subtlety from the changes, or the extra dimension that Mahler's music can provide of a huge orchestra blowing your senses by playing perfectly together.

There were some great moments last night - the beginning and end of the first movement were outstanding, as was the offstage brass section at the end of the second. But while I realise that, in the words of one commentator, "there will never be a perfect Mahler 8", I'm hoping for better next time. And I will certainly be trying again.