I personally feel that any big middle-period Beethoven work is so many-sided that I want to hear a diversity of approaches. Four favorites here, chosen to contrast as radically as possible:
1. For sheer theatricality one can't beat Gardiner. Clearly he regards it as a very exciting work but not a very great one; he doesn't find in it the kind of substance that might be expected in a work contemporary with the Razumovsky Quartets and the Fifth Symphony.* (I'm not complaining about his approach, merely trying to describe it as accurately as possible.)
2. The exact antithesis is Giulini: he is as totally (one-sidedly?) reflective as Gardiner is theatrical. Everything is slow, sensitive, reverential, reverent. Very similar, in fact, to his famous recording of the Missa Solemnis: anyone who likes or dislikes that performance would be likely to respond the same way to this one.
3. Then there's Beecham. Beecham obviously cherished this work for an idiosyncratic reason: it's the most Haydnesque of Beethoven's major works, and Beecham frankly preferred Haydn to Beethoven. So, one's attitude to this recording is likely to depend on one's attitude to Beecham's Haydn. (And on one's tolerance for 1950s fuzzily recorded choral sound.)
4. Among recent recordings that I've heard, I've enjoyed Jansons most (on DVD--is the CD the same performance?). I'm not sure that Jansons had as much innate talent as either Gardiner or Giulini or Beecham, but he gives me the impression that he really loved & admired this work, treating it as though it truly is a perfectly standard middle-period Beethoven masterpiece. Of the various recordings known to me, this may be the none that offers most of the kind of constantly shifting interplay one customarily hears in Beethoven's symphonies & quartets--light & shade, tragedy & triumph, conflict & conquest intertwined. On the other hand, it doesn't offer (or even attempt) the singleminded intensity of Gardiner & Giulini (in their very different ways).
Did Bernstein ever perform this Mass? He might have done it particularly well; he was at home in both Haydn and Beethoven.
* Chronological position:
Symphony No. 3, "Eroica" (Op. 55; 1803)
Piano Sonata No. 21, "Waldstein" (Op. 53; 1804)
Piano Sonata No. 23, "Appassionata" (Op. 57; 1805)
Leonore/Fidelio, first two versions (Op. 72; 1805-1806)
Symphony No. 4 (Op. 60; 1806)
Violin Concerto (Op. 61; 1806)
String Quartets Nos. 7-9, "Razumovsky" (Op. 59, Nos. 1-3; 1806)
Piano Concerto No. 4 (Op. 58; 1807)
Coriolan Overture (Op. 62; 1807)
Mass in C Major (Op. 86; 1807)
Symphony No. 5 (Op. 67; 1808)
Symphony No. 6, "Pastoral" (Op. 68; 1808)
AFTERTHOUGHT
Does anyone have Segerstam (on Naxos)? I imagine the Mass might suit his style well, but on listening to samples, I was rather doubtful about the quality of the chorus, so I've been hesitant to buy it.