There isn't much info about the IGI on head-fi - so I figured I'd make a post.
At work I needed closed headphones which led me to M50's - they isolate fairly well, and sound good - but the "Grado" sound I have grown to love wasn't there. The M50's bore me with their laid back mids, and left me wanting something more fun to listen to.
IEM's aren't my typically my thing, but getting Grado sound in a sealed headphone just isn't going to happen - so I looked at Grado's IEM line up. The IGI fit my budget - so I ordered it.
Quality - they are generic housing with a cheap feeling cable, no surprise there.
Accessories - they come with quite a few different tips, no carrying case - but once again no surprise.
Isolation - better than the M50's but could be better. At low volumes I can still hear the surrounding environment.
Sound - here is where they shine. I wasn't looking for the best IEM in this price range, I wanted Grado sound - and Grado sound they have. I don't know how they did it - but they sound open, airy, and just rock.
No amp needed for these either, they are very efficient.
Overall - you want Grado sound with isolation and no leakage, look no further - buy them.