I have to share my happy experience with the SX-980. I had some early problems on the eBay purchased receiver with idle current imbalance and the protection circuit tripping. I then accidentally popped some things on the PS board trying to self-diagnose it before I called for professional help to get it up to snuff.
Meanwhile, I repaired the foam surrounds and recapped my 1981 Bose 601-I's (I don't want to hear the dissing). They can take everything the 980 can pump out up to my own hearing tolerance level. My brother bought some 601-IIs a few years after mine that also had rotten surrounds. I fixed them and have wired all 4 of them to the 980. The S-1's have much more bass response, and a flatter midrange than the S-II's which have clearer and well defined midrange. With A+B, I cannot crank past about 2:30-3 until it is simply unhealthy. I have tried a set of Boston Acoustics VR-40's that have beautiful midrange and presence, but poor low end punch (designed to run with a sub). Interestingly, they are rated at 8 ohm, but will consistently trip the protection circuit on the receiver at about 15W output. I'll have to give the S-II's back soon, but am immensely enjoying the beautiful overall balance of the 4 601's while I have them!