I got myself a box of raptors a few days ago, and I've taken a liking to them when I swapped them with my Berserkers. Comparing them to a Berserker, it's no wonder why these guys are so much better than a berserker. Let's look at the stats and points.
Stats wise, what does a berserker offer? Outside of an in-built mark of khorne and WS5, they don't really have anything else to add outside of chainsaws (which grants AP4. Wooooow.) and their slowass slogging requires them to possess a Land Raider if they want to get anywhere else. All these effectively leads to a hefty 400 points, or more, for a 10 man Berserker Squad with Land Raider.
Now, let's look at the Raptor. Effectively just a marine, okay. But they have jump packs, which mean they can either move 12 inches on the movement, or reroll charge distance on an assault. Okay, that's one advantage over the Berserkers, being able to move 12 inches on your movement meant you're pretty swift on your feet. Add in run, and you're looking at the ability to move an average of 15-16 inches per turn, which means running around in circles or taking out isolated targets. What else can they do? Throw mark of khornes into them, and you're looking at a +2 Attack instead of +1 on a charge. Very nice. Add in an Icon of Wrath, and you can re-roll charge distances!
Yes, with 12 inch movement and a reroll your charge, you effectively just created a squad of Berserkers with jump packs, which you can also outfit with 2 meltaguns for an added anti-vehicle punch. What are you sacrificing? a +1 to your WS and Fearless. Minor details! If you're using a bike lord (or jump pack lord if you're feeling cheap.) You're already effectively fearless by attaching your Chaos Lord to them! You can't deny how useful having that extra mobility is, without needing a rhino or a land raider just to get their butts into combat. If not into combat, then just jumping into the enemy's face to deny objectives! Best of all, with Mark of Khorne, Icon of Wrath, 2 meltaguns, and maybe a combi-melta/combi-plasma and lightning claw upgrade to the sergeant, you're looking at a measly 280 points for a flexible squad.
So, in summary:
+ Extra killy power in the form of +1 WS and Attack
+ Free Mark of Khorne
+ Troop choice if you take Chaos Lord with Mark of Khorne
- Not very mobile
- Needs Land Raider to penetrate enemy tender nether regions
- With that cost it comes to about 400 pts, 240 if you go for a rhino instead.
- You can't take Meltaguns
+ Mobility (12 inch movement)
+ With an Icon of Wrath, you get to reroll charge distances
+ Meltagun equippable.
- Less 1 attack and 1 WS than Berserkers
- Not fearless on their own
- Not a troop choice
- Bulky (but who the hell puts them in vehicles anyway?)
In summary, if you're the guy who like super violence and you're taking a Land Raider anyway, then the Berserkers might be a good choice. But if you want flexibility and the ability to adapt given the situation, then take the Raptors instead.
Might be making a new list soon. Fluffy the terrible has not served me well, so what am I going to do? Well, let's just say that a bunch of Traitorous Guardsmen are going to be serving their Chaos Masters with artillery soon...