Stokes pulses of high energy and high-average power were obtained by stimulated Brillouin scattering (SBS) compression of long Nd:YAG laser pulses. The SBS medium used in the single-cell compressor was liquid ultrafiltered Fluorinert FC-75 fluorocarbon. An output pulse duration of 0.9 ns and a peak-power enhancement by 1 order of magnitude were observed for 10-ns, 0.57-J input pulses at a 10-Hz repetition rate. The compressor internal SBS efficiency reached a value of eta(SBS) = 94% and the overall device efficiency a value of eta(dev) = 87%; both values are the highest reported so far to the best of our knowledge. The simple single-cell SBS geometry provided excellent energy and pointing stability of the Stokes pulse. Its temporal shape turned out to be somewhat less stable. The SBS process also partially improved the laser beam quality. The Stokes pulses proved to be capable of generating radiation in the extreme-ultraviolet and soft-x-ray regions over a period of two months without any significant output deterioration.