Just wanted to share one of my current FAVORITE UNITS. My Blood Angels Deredeo Dreadnought.
Now you may be thinking "You play Blood Angels, why is this your favourite unit?" Well...
1- Even an assault army needs some ranged weapons. And this guy is super reliable at that.
2- I love dreadnoughts as much as I love assault
Some quick tactics talk with this guy
DREADNOUGHT FORT
SO I run mine equipped with the Atomantic Pavaise (I used a Magna Grapple I converted for my Contemptor back when they could still take one. This is because FW still has not released that upgrade). This gives a bubble of a 5+ invuln to units within 6". So what do I do? I surround him with TWIN AUTOCANNON MORTIS DREADNOUGHTS! This creates a rock solid fire base of High T and a good save (2+/5+ on the Deredeo, 3+/5+ on the Mortis) and a lot of wound (4 dreads castles up is 44 wounds). And at a very reasonable points cost IMO.
Now I could keep Characters near them to boost them, but if this is not possible, I just use my Wisdom of the Ancients stratagem on my Deredeo, turning him into a captain for the turn. This force multiplies the Mortis in turn.
Don't want to use Mortis? Consider Devastators, Rapier Carriers, and Hellblasters as candidates for this Aegis and Reroll buff.
In one turn, I have killed a Mortarion with 1 Deredeo and 2 Mortis this way. It is great.