So I got to try out my horde for the first time today, so I felt it would be worthwhile to share my experience:
My list was using Alpha Legion (for that sexy -1 to hit).
3x 5 man Plas, Combi-plas CSM squads
3x 10 man Noise marine squads, decked out fully
1x 6 man AC havoc squad
1x 6 man HB havoc squad
1x 5 man Melta havoc squad
10x Khorne Berserkers (6 axe+Chainsword, 3x BP + chainsword)
Jump lord w/ murder sword
jump sorc w/ death hex + diabolic strength
foot lord, naked
foot sorc, prescience + delightful agonies
exalted champ w/ black mace
Played against a Space Wolf, so not exactly the most dangerous codex in existence.
6x thunder wolves, TH+SS
Wolf lord w/ frost axe
Relic Sicarian Punisher
LR Crusader (11x blood claws, Lukas, Arjac)
5 man Intercessor squad
10 man Grey Hunters, double plas, combi-plas
Battle Leader w/ power fist + combi-plas
3x aggressors (bolt + fragstorm)
Pretty character heavy army, and fairly aggressive. I deployed cautiously, was able to go first but didn't do much but take a handful of wounds off the LR with my blastmasters and autocannons.
As the SW got closer, the bulk of my army was able to come to bear, with the LR and all its contents killed having only taken out a few of my marines with hurricane bolter shots. By the end of the 2nd turn, the sicaran was down a bracket, and only the thunderwolves remained within threat range.
The battle was pretty one sided at this point, so I opted to charge my jump characters and 'zerkers into the Thunderwolves to get some proper melee in, but failed to get Death Hex off. The wolf lord died horribly to the murder sword (as is tradition) but the opponent expectedly interrupted to hit the 'zerkers with the wolves. The marines riding them whiffed, but the giant puppers themselves took out all but one 'zerker.
I withdrew from combat, honour being satisfied, and wiped out everything but the Grey Hunters at the start of turn 4. The opponent failed to draw any maelstrom cards which he could go after with the hunters (as we were fairly close in VP all things considered, owing to my less than optimal combat choices), and failed, thus conceding.
I didn't end up losing any models to morale losses, despite having 4 10 man units worth shooting at, so for the time being the extra resilience of Alpha Legion is what I'll stick with, as the opponent despite having some alright anti-infantry shooting (aggressors, sicaran, crusader, intercessors) he really didn't do much damage due to that -1, which is especially brutal when using assault weapons or heavies after moving, reducing marine shooting to 5+.
I shall continue to experiment and report my findings on the glory of the Marine horde.