The biggest advantage to becoming a Crab Spider is that stylish backpack. Yes, there is a color-customizable version. Yes, it works just fine with capes, assuming you can ignore the slight clipping issues involved. Yes, it looks most "normal" on top of the archetype-specific Crab Spider armor, but it's a lovely addition to any outfit.

A crab's primary powers largely mirror the "base" powerset with a few alterations. You gain three ascending ranks of ranged attacks, two single-target and one conical. You gain access to both Venom Grenade and Frag Grenade powers, and can only take either the basic soldier power or the crab spider version. The biggest changes early on are the addition of Arm Lash (a cone-area melee attack), Slice for Defense reduction instead of Pummel's Disorient, and Aim instead of Wide-Area Web Grenade. Later on, you also pick up Frenzy (a point-blank AoE melee strike) and Omega Maneuver (a bomb that disorients nearby enemies before detonation).

The secondary side is fairly unchanged. You gain an upgrade to your armor's resistances (which can co-exist with your Wolf Spider Armor for some high durability), a health buff via Serum, and a tank toggle for more resistances. You can also summon Spiderlings at the end, which should prove amusing for those who can't get enough of spiders.

Crabs don't suffer from a dearth of options. You can go down the route of becoming an ersatz tank via your toggles, resistances, and Serum. (Provoke would be a good call here.) You could also focus on a durable melee build with your armor and a blend of the various melee powers, or the same thing with range (especially with the addition of Aim). If there's one overarching theme, it's probably pushing you toward heavy AoE damage and the durability to survive anything that decides to yank on to you. Slice is largely worthless, Venom Grenade remains excellent, and Omega Maneuver is a decent panic button.

Quote from Massively