PCR for generating radiolabeled probes?

[RICHARD P. PHIPPS]

I once tried labeling a PCR product (350 bp) by reamplifying (PCR) the
fragment in the presence of CTP, GTP, TTP and 32P-ATP.  However, this 
procedure did not appear to yield a probe which was hotter than if this 
fragment was randomly-labeled following a standard protocol.  Has anyone
conducted a more scientific comparison of these two procedures.  What
was found?  Moreover, I have read advertisements for radioactive-PCR-
labeling of probes which claim this technique yields hotter probes than
conventional random-labeling.  Could anyone enlighten me on the advantages
/disadvantages of these two procedures?  Your time is appreciated.

Thanx
ERF