@CrackRockSteady @Axi5 That two models was just an example, not specific models I've got problem with. Thanks for discussion, I didn't expect so many posts :) So it really depends on the situation and lead/client wish.
@Axi5 You know to be honest, it is entirely possible that the OP was asking specifically about large forms interpenetrating a lot, in which case you're absolutely right about the points you've made. I assumed he was asking a very general question but I could be wrong about that.