I think Sasori is extremely underrated. People think that because he lost to sakura and chyio he is weak. But it's not true. Sasori lost to maybe the only person who knew his techniques and style (chyio) and a person who could create an antidote for his poison (sakura). You could not have asked for a better match-up against Sasori. And he is an extremely good counter for Itachi. One of the best shinobi to counter Itachi in the akatsuki.