Wait to hear your ATC's. They are a truly great speaker. I'm a musician who has spent years in studios. The ATCs are the best monitor speaker I've heard.
Rather than get a more expensive (but not necessarily better sounding speaker) I think you want to hear them with your NAD. Then if you get the upgrade bug, think about buying a better integrated. Or don't submit to the deadly upgrade virus and just buy more music. If the system is in a small room, you may have hit on a nearly ideal combination.
Seriously, the Dynaudio 1.3se's are very nice. They equal the SCM 7 in some ways but not others. While the Spendors and the Dynaudio 52's will play lower notes in the bass, I don't think they are nearly as accurate as the SCM-7s. ATC makes wonderfully revealing and musical speakers. It is hard to find that combination in any other speaker line. I can say that because I've owned Apogee's, Vandersteen's, Snell's, Watt's, and Sonus Faber as well as ATCs. I've had happy musical moments with each. I don't even own ATCs at present, but I regret I sold mine and will probably get back to them after I pay off my remodel.
Whatever you decide to do, good luck.
Matt