1. The one class that this choice makes sense. You aren't/shouldn't be carrying grenades and will be front line enough to possibly kill enemies trying to mind control you.
2. Assault actually uses double shots a lot and won't be shooting from height + distance
3. You don't want to lose will and snipers + MEC's will be doing 80%+ of all killing
4. This could go either way but it is WAY expensive. If you have the MELD to burn fine, otherwise...
5. The other choice is utterly worthless. This choice is expensive but OP. Don't die mid-end game.