This is just my opinion from personal ranked and casual conquest, and from watching a lot of SPL. I've seen what Gods work well with certain types of comps. Some Gods are more situational depending on the comp; hence, will be given a lower tier.
I will try to be as objective as I can. I pride myself at knowing all of the Gods and roles in Smite. I am pretty familiar with the entire roster.
My favorite Gods in each role (just personal favorites) :
Carry: Jing Wei
Jungle: Hun Batz