As with many subsequent attempts, it has too much power at the 20 and 40 Kyr frequencies and too little at 100 Kyr (this is by eyeball), but does get the dates of various maxima of glaciation quite closely. The paper itself believes it is quite accurate out the the dated reversal at 700 Kyr; another paper I read (ref. forgotten) referred to this one as quite accurate to about 150 Kyr.
My chief interest, however, is in its figure 2, which shows what this model predicts for the next 120 Kyr: increasing ice volume. Whether this is intended as a prediction is not clear to me: it says that "large areas of North America, northern Europe and the USSR will have to be encrusted with ice cheets during the next few thousand years, to fulfil the expectations of figure 2.", but gives no indication of whether it considers this likely to happen or not. On the other hand, extrapolation of the curve is described as "a first-order forecast". Ho hum. N. Calder points out that he intended this to be a prediction: "yes of course I was predicting a new ice age".