I would still consider a hero sailor over a super elite for engy. The reasons:
- super elite has only +1 eng stat more (that small difference can be easily bridged by putting more vets on)
- hero has +14 rep/rest (super elite only has +10)
- for one super elite you'll get two heroes
Super elite sailors, in general, aren't so very useful, because of caps. You might save a bit of weight maybe (taking off crew after having reached the cap), or gain a few seconds of OH in the case of engies. The only ones that are clearly superior are fighter super elites, if there is no fighter cap.