Effectively, these guys are close combat assault squads, without the jump packs on their backs (which they can take). To be honest, they're a little bit like Khorne Berzerkers or Khorne Bloodletters in some respects: improved WS, counter attack, etc. But, here's a few catches: they're all characters in the squad and must all accept and issue challenges (as if they're 40k chaos space marine characters).
They are all issued with Charnabal sabres: a rending weapon that also gives +1I in challenges: these are a great addition to the squad and can come in very handy.
Here are some sample builds:
5 Palatine Blades; 2 power lances, sonic shriekers, melta bombs (160 points)
A squad that is meant to advance up the field, shooting their pistols along the way and charging whatever comes in range. Place in a drop pod, rhino or land raider to taste.
5 Palatine Blades, jump packs, melta bombs, sonic shriekers, power sword on prefector (205 points)
A dedicated, elite assault squad. Enough said. Except that its a bit pricey.
5 Palatine Blades, jump packs, melta bombs, everyone with power swords or power lances, sonic shriekers (225 points)
The maxed-out squad. They're bloodletters on wings. With power armour. Deal with them or there's going to be a lot of dead loyalists (or even traitors?!).