Beethoven's Mass in C Op. 86 has never received the same recorded attention as the Missa solemnis, but there are still several excellent recordings to choose from.
John Eliot Gardiner's reading (Archiv 435 391-2) is an easy first choice. Both the singing and the orchestral playing are top-notch. The Monteverdi Choir sings with flawless choral blend, precision in diction and intonation, and convincing phrasing—a joy to listen to. The Orchestre Revolutionaire et Romantique, utilizing period instruments, plays with equal precision, and a vast palette of tonal color. No thin sounding strings or shrill winds here—just first-rank playing with an almost fiendish energy. The soloists are well up to the standards set by the choir and orchestra. The voices are a bit larger and more full-bodied than in many "period" instrument recordings, and the color suits the music perfectly. Be advised that the orchestra tunes to A=415 rather than the contemporary standard of A=440 so you won't be able to play this recording and play your part along on your piano when you study.
Robert Shaw's 1990 recording (Telarc CD-80248) is a "big-band" performance with precision and beauty of tone in both the singing and playing, and more expansive tempi than Gardiner. The deliberate tempo of the Gloria (it runs two-ahd-a-half minutes longer than Gardiner) is weighty and grand as opposed to light and exuberant. But, as always with Shaw, there is great beauty in the performance, including wonderful contributions by all the soloists. The sound is typical Telarc, clean, round, no brittleness, but with the chorus set a little further back in a rather gauzy acoustic.
Sir Thomas Beecham's 1959 recording has long been a yardstick of measurement for performances of this work, and is available in a budget-priced 2-CD set coupled with Beethoven's 2nd and 7th Symphonies CD (EMI 0724358650426). The Beecham Choral Society's singing is definitely '50's vintage. Their performance is colorful and meaty, if somewhat lacking in the precision and perfect blend of Gardiner's forces. The team of soloists is evenly matched, and more operatic sounding than Gardiner's quartet. The performance has wonderful energy and pacing, with tempi almost as crisp as Gardiner's. The sonics are good, if slightly edgy and brittle by contemporary standards.
Colin Davis' recording is available as part of a 2 CD set (Philips 438 362-2) with the Missa solemnis at a 2 for 1 price. Definitely a great way to expand your Beethoven choral music collection. The performance is conservatively paced, but even the tempi that are slower than Shaw's have a forward momentum that give direction and dramatic presence to the music. The London Symphony Chorus' performance is mostly first-rate, both technically and musically, with all sections well up to the task. Only in the Crucifixus, does the blend get rough. Warm, vintage Philips analog sound has been retained nicely on the CD.
Lighter-weight, intimate, and currently out of print, is George Guest's performance with the St. John's College Choir, Cambridge (last in print as London 430 361-2). The pleasing clarity of the boys' voices allow for well-delineated textures, and though the grand moments are sometimes lost due to the intimacy of the forces, this is a lovely performance to own if you can find it.