Many worthy nominations but ... I've said it before, and I'll say it again, DAVID RUFFIN was the absolute greatest by a mile !
Both as a VOCALIST and PERFORMER !
As a vocalist he could tackle literally ANY style of music (soul funk r'n'b country etc) , and he could croon and do show tunes too like Jackie Wilson ...
As a performer he was as agile and athletic as James Brown and Joe Tex , and he had all the moves with the Temps. Just look at some of the videos on this site with Ruffin in them !
Marvin , great as he was , wasn't much of a dancer and by his own admission felt uncomfortable doing gritty RnB as on his earliest hits. As we all know Marvin wanted to be like Nat King Cole !
There were absolutely no limits to Ruffin's talent ... his only problem was that he knew it too , he had a massive ego ..... still, he was the best !