After buying both of them and playing through them on my second playthrough, I can't help but think that Pinnacle Station was a much better value proposition than Bring Down the Sky.  
 
Bring Down the Sky featured a bit of a story, voice acting, but all it boiled down to for me was just another generic planet (asteroid in this case, I guess) that I did a side-mission quest chain on. The ~2 hours or so it took to complete didn't really make it stand out in my mind as a good purchase.
 
Pinnacle Station had a pretty challenging set of missions (the last four) that forced me to level my Shepard up on other side-missions before coming back. While the combat in ME can be super jank at times, I never felt like I was unable to complete a mission because of it's flaws. I felt that I could complete them all with relative ease, with the exception of the last "Capture" mission, where I ended up retrying it for ~30 min or so because I kept missing the top time by a few tenths of a second. After everything was all done, I got a cushy pad on some planet too, and an awesome loot generator!
 
As they were both 400 points when I purchased them, I honestly feel like Pinnacle Station, while lacking story, really enhanced my gameplay experience while Bring Down the Sky felt like much less content for the same price. 
 
So I ask you guys, what was the better value proposition?        

I enjoy story, and Bring Down The Sky has a neat bit of additional fiction that's worth checking out.

I clicked Pinnacle but I meant Bring Down the Sky. 
Bring Down the Sky just had a much better choice at the end, and introduced a cool new race of characters.

Bring down the sky, because mass effect is about story, though I did LOVE the salarian from pinnacle station. Oh sarcastic salarian, how I love you.

I enjoyed Pinnacle Station because it made me pick up the game I love so much and play it again with new content, but Bring Down the Sky did that too with better story :P

Bring Down the Sky. More length means nothing if it's boring.

Bring Down the Sky was alot better and it should be the one people buy because it introduced some interesting story and the Batarians 
 
All things considered though, Bioware should make better DLC in the future

Pinnalce Station is terrible. It's all combat focused and that's not the best aspect of Mass Effect in the slightest.

I enjoyed "Bring Down the Sky" more because it doesn't detract from the main game.  It features a well-fleshed out side-mission, of which you can decide the outcome for, pretty much what you're doing throughout the entire game.  I felt that "Pinnacle Station" focused on the lackluster combat that Mass Effect offers, but it was a fun experience all around.

Pinnacle Station has more achievements. Done.

Bring Down The Sky. There's no competition here.
 
Pinnacle Station was a mess. It tried to introduce multiplayer shooter style modes into a game where the shooting is NOT it's strongpoint.