Homogenous vs heterogeneous unbalanced Feistel networks?
There is no “generally definable” security trade-off, unless there’s something wrong with one of the algorithms itself… and if, that could be proven easier in the case of homogenous UFNs.
Using homogenous UFNs makes security proofs easier as they are easier to analyze while heterogenous UFNs tend to make cryptanalysis (and security proofs) more problematic. This can be a valid argument to choose a homogenous over a heterogeneous UFN.