This is not a buffet but wing hongs express on Union Lake road next to dunken donuts is amazing. Their prices are beyond fair and you get enough food to last you 3 days. On top of that they actually have legit egg rolls, not the ones stuffed with cabbage.
I have not been there in years but there is a chinese buffet near Harbor Freight in Pontiac off of I believe Elizabeth Lake rd. If your heading down Elizabeth Lake road from harbor freight it is on your left in about a mile or two away. They use to have an awesome buffet, unsure of if they still do or not though.