I think it's a matter of your needs. The 950 was, and is, still a great sounding processor. As a newer design, the 990 adds some things that are relevant to many, while others are correct that the 950 still meets their needs. I'd take the 990 for the lip sync delay that is a real key item thanks to the delay caused by my digital TV and cable box+PVR, the USB port to connect PC audio for new stuff while the phono input gives you a chance to still play records. DVI is a big plus and the upgrade port certainlly gives you something to guard against the future.
YMMV