Bruckner's Psalm 150 is relative easy to find, and the piece(s) it's coupled with on different CDs might well determine which version you wish to purchase.
Wonderfully successful (as would be expected!) is Helmuth Rilling conducting the Gächinger Kantorei Stuttgart and the Bach-Collegium Stuttgart (Hänssler 98.119, coupled with Bruckner's Mass No. 2 in e minor and the Te Deum). The soprano tone can be a bit "screamy" above the staff when singing at big volumes (almost unavoidable when singing sustained high Bb above full orchestra!), but the drama is winning—there's a reason we say "Rilling is thrilling"! And nobody controls those tutti luftpause like Maestro Rilling.
One of the classic recordings of Bruckner's Psalm 150 is Eugen Jochum conducting the Chor der Deutschen Oper Belin and the Berlin Philharmoniker (Deutsche Grammophon 457 743-2, mid-priced and coupled with the Te Deum and a generous selection of Bruckner's a cappella motets). The choral singing is vintage; rich, full-throated, colorful—and often without a real sense of "blend" (neither vowel, vibrato, or timbre). In fact, in some of the softer passages, the competing vibratos rather obscure the pitch. But, this is still a wonderful performance—passionate and committed. Recorded in 1965, the sound also vintage DG: warm and detailed analog with a terrific sense of space and depth.
If it's clean you want, it's clean you get with Matthew Best conducting the Corydon Singers and Orchestra (Hyperion CDA66599). This is British Cathedral choir perfection (though a mixed choir of all mature voices) delivering a controlled but never staid performance. Wonderful choral tone, exacting attention to detail in diction and ensemble, and the best recorded sound of the three Bruckner CDs on this list.