wye-1/8th(combination) vs. a wye + 45

In general, is there any difference in performance between a "wye-1/8th(combination)" vs. a "wye + 45"?

I would think a "wye + 45" is better since there is a longer sweep which gets the waste flowing in the right direction for a longer time helping it downhill whereas a "wye-1/8th(combination)" would be more likely to "plop" it down like a regular sanitary tee in that configuration. Is this correct logic?

Neither is similar to a sanitary tee.

There is no functional difference between the two. The difference is the cost of two fittings versus one and the elimination of one joint/connection.