There are many distinctions to be made. For the most part, removal at the least of all of the hot break is necessary to avoid difficulties in clarification, decreased foam stability, and rapid staling of the beer, while cold break removal may be less critical. But in some cases a limited exception may occur; for example, with a weak yeast crop or inadequate oxygenation, a small amount of hot break carried over may provide nutrients that improve yeast health and its ability, downstream, to bind proteins, resulting in clearer beer with better foam. However, the same trub carryover can in fact lead to these very deficiencies in the yeast. These are just a couple of illustrative examples. Many complicated factors must be considered together. (Hence I think many of those homebrew experiments comparing "all or nothing" are invalid, because they don't take enough variables into account.) The same brewer may, in different circumstances, choose to alter his process. She may choose to separate all the break after chilling, separate the hot break but carry over cold break, something in between, or not worry at all and let things sort themselves out. And so on.
But to the point:
What bothers me is this: As a brewer, I want to make my own decisions and control my processes for sound reasons, addressing conditions I am confronted with and goals I set, founding my decisions on solid understanding of brewing science and technology. I don't want my choices to be limited or dictated by the inflexible design of a piece of equipment, whose designers seem not to have taken any of these issues into account, or possibly even have been remotely aware of them.
[Note that it's not just about trub. This applies to every element of your process from grain to glass.]
Consider this before investing in any monolithic, fixed brewing system.