Sanguinary Guard received a massive drop in points cost in this codex, with their rules and options staying pretty much the same. The big exception is that squads can now be increased in size, up to ten. They still come with artificer armor, encarmine swords (which they can switch out for encarmine axes or power fists) and angelus bolters (which they can upgrade to inferno guns or plasma pistols). The squad can take death masks, making them cause Fear, for a very reasonable point cost. The best upgrade is the Chapter banner, which grants every model in the unit an extra attack as well as providing the standard morale bonuses.
I think Sanguinary Guard squads work best in large squads, acting as your focal assault unit. I try to take mostly swords, with a sprinkling of axes and power fists for some AP2. I will also usually take a few inferno pistols so the squad can take out armor if needed. The most important addition is the Chapter banner; the extra attack is what really turns Sanguinary Guard into a serious assault unit.
To really fulfill their potential, Sanguinary Guard are best joined by a Priest. They really benefit from Feel No Pain, and WS 5 will reduce their number of missed attacks to the point that their master-crafted weapons will allow them to re-roll most of their misses. They also really benefit from being joined by Dante (what squad doesn’t?) because he gives them Hit and Run and AP2 attacks at high initiative.
One important consideration when playing Sanguinary Guard is whether to shoot before assaulting. Their angelus bolters are actually pretty good guns, and a large squad will do a lot of damage to any target with 4+ armor or less. There’s every chance that you’ll shoot yourself out of assault range, so it’s often better to hold fire against such targets.