Brittle or Serpent sea star?

[Mebbid]

I've been wanting a starfish for quite a while now and was having a hard time deciding between the two types. Are there any pros or cons between the two different species? Is either easier to care for than the other? Is there a reason Brittle stars are labeled Semi Aggressive by Liveaquaria while Serpent stars are peaceful?

I have a 20g nano reef with a 10g refugium. The tank has been set up for a little over a month now.

As far as stocking:
2x clownfish
1x Firefish
1x Scooter Blenny
Assorted snails and hermit crabs
Pincushion urchin
Assorted Mushrooms and Zoas

 

[54seaweed]

I like serpents I have 2 in my 37g
they do get big though I have one almost 12 inch
he reminds me of a octopus

 

[Fish4ever]

Harllequin serpent star coolest thing out there

 

[JumperAlex]

I had a green brittle star in my 36g with 2 clowns and a cardinal. The brittle star ate my cardinal one day without warning! Crazy thing. I'll give you this one if you want it.