Your success will depend largely on what you are selling, and how well you advertise/how many items in your inventory at any given time/etc.
I don't sell anything on eBay except for used clothes, but I definitely prefer Etsy. You're catering to a more specific crowd, I feel. That may be just my opinion. I wouldn't sell my vintage items on eBay, for instance (again, that's just me).
I've been here a little over a month, and I already have had a few sales. I'd say that it's worth it to be here.