In 5th Edition the BA assault marines are troop choices, not fast attack and can take 2 meltaguns in a 5 model unit, Jump pack models only scatter 1d6 instead of 2d6 (Descent of Angels), BA Land Raiders can deep strike, BA units reroll their reserve rolls if they fail (upgrades a 50% to 75% chance to come in on deep strike on turn 2), 5th Edition you can have your entire force in reserve and you don't auto lose if no models are on the board at the end of the battle round, BA Vanguard Veterans can assault on the turn they deep strike, etc etc.