I find the IA story to be very overrated, it has a few interesting twists and two very good chapter endings (1 and 2), but it's nowhere close to what people seem to think. My personal favorite is Jedi Consular though, don't care what people say, I love the mystery aspect of it. BH has some really great companions who make the story much better than it would have been otherwise. Both JK and SW does exactly what you expect, which is both good and bad. SI has an interesting basis, but oh dear that chapter 2 throws everything off the path. Smuggler and Troopers are both kind of....meh in my opinion. Good in theory, but feels more like watching an episode based TV show, nothing really keeps the different planets together.
My personal rating would be:
That said, everyone has a different opinion, and none of them are wrong.
I agree about the IA story, just finished it a few days ago. I now have a 50 BH and IA, and I'd have to say the IA story is great but not amazing.
I wanted to comment on what you said about BH's though and point out that its important to remember some stories are better in different areas.
While I'd say the IA had a much more complex, intriguing, and gripping story, the IA's companions were weak. In the BH story you actually feel like a team. It's commonplace to be having conversations where all the companions gather around the holo-terminal and decide how their going to go about the next mission, your dialogue choices earning/losing you rep for ALL your companions at once. You feel like you're in a kick *** BH team with your character as the star and leader.
In the IA story your companions feel like they are all connected to you, but don't want to interact with the other companions much at all. Your companions are seriously all gathered for a conversation a number of two, maybe three times.
Overall I'd have given the BH story an 8/10 and IA 8.5 or 9/10.