Do you mean the Panasonic DMR-EX77? Great recorder, but not sonically in the same league as the Sony - and I wouldn't expect it to be, as it's a cheaper machine (list price £350, available for £250).
Sorry, but DVD players start with a major disadvantage when it comes to playing music, and adding recording functionality doesn't help matters, so you need to invest in higher-end kit to get any hope of a decent stereo sound.
FYI, we're Group-Testing a whole host of DVD Recorders - including a brand-new Sony, plus models from LG, Samsung, Panasonic and Toshiba - in our next issue, out 26 July (with subscribers the preceding weekend).