Nolitan:
I have a Koetsu RSP and have used a bunch of different SUT's. The Altec 4722 and Cinemag are very similar. Not suprising as the Cinemag and Altec were designed by the same family (Father = Altec and Son = Cinemag). Between the two I'd choose the Cinemag only because any Altec used today is a NOS product as they have not been manufactured for years.
However, for my $ the SUT's I prefer with the Koetsu are the ones from Hashimoto. I get more detail with the Hashimoto and it also throws a larger soundstage. Only downside is that its also more expensive. John at Choir Audio sells both the Cinemag and Hashimoto products. His prices are very competitive.