Depends on what you are going to be facing. If that BAO guard list catches on things are going to be interesting to say the least.
For the most part in 8th I find you need to be able to deal with 3 things:
1. t3 spam. Conscripts, bugs, etc. (power scourge / missile launcher
2. 16+ wounds models. knights etc. (missile launcher / lascannon / multimelta)
3. 2+ wound elite infantry. (power scourge / Fist / Plasma)
A mix of Missile launcher/plasma/lascannon with some melee sprinkled in would probably be good. I would favor the scourge over fist because of horde armies.
I saw a battle report that was all hellbrutes vs dreads back in 7th. It was amazing, youre going to have fun with an army like this, especially with 8th ed rules.