The lights are on
Yes you should get Dragon Age 2 and here are couple reasons why:
1. Its a fun game.
2. It continues the story by carrying over data from Dragon Age: Origins.
3. It's data will be imported into Dragon Age 3.
Just keep in mind that just because its different from Origins, does not make it a bad game. Its fun, has cool characters, and cool story. Just remember there are not as many options like Dragon Age: Origins.