It did start out slightly slow before becoming awesome, but yes you should avoid it. Although it was awesome, they cancelled it at a pretty gigantic cliffhanger in both the main plot and (surprisingly compelling) romance plot. I got to the last episode knowing it was cancelled and was so upset I wished I hadn't watched it.

Edit since I see now there may be some ambiguity - my comment here is specifically regarding Outcasts, not Firefly. I don't think (or didn't see) the Firefly reference was there before their edit.