It doesnt really matter that much if you have 5 eng / 5 sci / 5 tac in group or mix of them, and what kits they wear. It can help to have balanced group with best kits to finish Infected faster, but its not vital at all. Crucial is to have group made of players who know what to do, can do jumping without falling down to plasma all time, can pull borg groups one at a time after destroying node etc. The problem of most groups not able to complete Infected isnt wrong specs, but complete noobness. Thank you for listening.
You can discuss this if you want... and have time.