I'll argue that for any ship with enough room for two or more HRPs and not on a super-tight mass budget, reactive always provides the best balance of resistances, except in those rare situation where you know you'll only be taking thermic damage.
Reactive has the least penalties to resistances, and most of the penalties to thermic damage evaporate with a two or three heavy duty HRPs. You can also use the light weight mod on it to cut it's mass to below that of basic reinforced, improve the resistances significantly, and still have more integrity than even heavy duty reinforced.
Resistances apply to modules, even external ones, so reactive provides a significant level of protection against missiles and weapons that tend to be good against hulls or modules.
Conversely, thermic damage, where reactive is weak, is mostly delivered by lasers, which normally have relatively severe drop off and less armor penetration value for a given size than weapons that deal other damage types.
The one weakness of note is to railguns which are a 50/50 split of thermic and kinetic damage, but this is a modest weakness and can be easily mitigated. However, if you have a ship fast enough to readily evade missiles and doge a significant portion of kinetic damage, you are better off with standard resistances to minimize the damage of long range hitscan weapons as much as possible.
