Paul Kletzki's Beethoven symphony cycle from 1964-68, with the Czech Philharmonic Orchestra, is not as famous as other cycles from the same era. However, it deserves to be ranked very highly, in the ideal Beethoven Symphony Hall of Fame. Because Kletzki's interpretations are nothing but first rate performances. If you're used to other, more "mainstream" interpretations, these recordings will show you a truer Beethoven, or at least a Beethoven that you haven't heard before. The power, presence, and passion of these performances are simply breathtaking.
The orchestra deserves a special comment. The departments play with an electrifying commitment, which might be a rare thing when it comes to standard repertoire works. It's like they played this music for the first time. If you'll not be moved by this, nothing ever will.
Finally, the Supraphone engineering is excellent, capturing the spaciousness of the fine Dvorák Hall of the Rudolfinum Hall in Prague.
In sum, this is a magnificent Beethoven symphony cycle to cherish. I rank it together with Klemperer's (EMI), Furtwängler's (Music & Arts, EMI), Toscanini's (RCA), and Weingartner's (Opus Kura, Naxos) as one of the best cycles on record. Warmly and strongly recommended!