like power fists for the most part. Your codex will have the rest of the rules. Decent at taking on big things.
To be honest though, neither option is good. In a regular marine army regular terminators are way better for the cost than the close combat kind.
Dark Angels 1750 win/loss Record
Win - 23 (Belial helped wreck Ryan's puny Eldar)
Loss - 13 (Brice's Necrons wiped me)
Draw - 2 (The 13th hold out in alpha take and hold)