Manda is superior until proven otherwise. However, Aoda is the second strongest among the other snake summonings
And how, pray tell, did you arrive at that conclusion? The Snake Sage at Ryuchi Cave that taught Kabuto Senjutsu shits on Aoda and Manda.
OT - Manda all the way. He was a true warrior with a brilliant attitude befitting his role and master. Requiring sacrifices for his usage, making snide remarks and threats, etc. Aoda comes off almost lowly, like a peasant. However, he does seem quite fast and agile by the way he dodged those Juubi clones. Manda casually slaughters him, though.
Manda's death was sickening because he could've have had a much larger role and not died in such a ridiculous, asspull manner. Real wasted character there.