Collins was better. Which is not a slight against Songaila- Collins was just really good. The fact that he only had 1 amazing season at Wake (as opposed to 4 good to great seasons by Songaila) doesn't diminish that fact. As a sophomore, Collins put up 19/10 on 63% shooting from the field. Songaila's only year close to that was his senior year, when he did 18/8 on 53%. I can't imagine what a Sr. John Collins would have done, especially given his development in his first 2 years in Atlanta.
But otherwise, I agree that in is Duncan/Rogers/Collins/Songaila for Wake post players since 1990, with Williams being 5th. If you expand back to 1980, I'm not sure how folks like Anthony Teachey, Kenny Green, and Chris King would slot in. I watched them, but not enough to have an opinion.