My observations throughout the years are that for the most part, tomatoes are tomatoes.
It is my opinion and experience that the sort of advice that suggests there are "special" disease problems with heirlooms in general (actually I prefer the term OP/open-pollinated, but that's a topic for another post), tends to come from folks who simply don't know what they are talking about and/or are merely (and inaccurately) repeating what they read or heard somewhere.
Now, I am not saying that there is no such thing as general hybrid vigor or heterosis when it comes to tomatoes. I have experienced it before in my own garden to some extent, but I have also seen plenty of F1 hybrids go down to or suffer from the same diseases that the other "heirlooms" in my garden did.
What most folks have problems with is foliar fungal disease (early blight and sometimes septoria - or edit/add - late blight). For the most part, there are not that many varieties (OP or hybrid) that show any significant tolerance to foliar fungal disease.
Of course, a few gardeners might have problems with fusarium (F), verticillium (V), RKN (N), which are all soil-borne, and can in fact choose to grow hybrid varieties that have those "letters" after them if they do in fact have those particular known problems. However - a "V" hybrid variety or "VFN" etc, certainly does not guarantee a completely trouble-free garden for anyone, even if your garden has any of those problems anyway. Tolerance =/= total resistance.
Gardening is like life - you gotta regularly do stuff to keep things going, and some years are better than others no matter what you do.
