Both are broken, and I feel really stupid not getting the SE215 for the same price after visiting this website. That was before I discovered this website though. Unfortunately I do not have a lot of experience with other IEMs, but for sure the new S4s will have slightly different sound (hopefully for the better), and more durability.
From what I have read (and what I have considered), the Gr06 for around $65 or less is one of the best deals you can find for it's price; I have considered getting it but I will probably try the Brainwavz R1 since it's only $35 (with this code: fb2012fiver you get extra 5% off) at http://www.mp4nation.net/brainwavz-r1-dual-dynamic-speaker-in-ear-earphones. Other than one reviewer who compared it to the infamous Brainwavz B2 (considered one of the best priced IEMs), there is only hype and speculation, and nothing else to back up how good it is, so it's best that you wait until next Friday (Brainwavz R1 sale ends at Oct 22, so you got about a week).
From what people say, Gr06 is probably the best for it's price, if you give it a week, the R1s could all of a sudden become the greatest IEMs to purchase for it's price, and you would have your winner. The S4s I have no faith in; sure they fixed the durability, but Klipsch hasn't proved their performance in headphones yet, and unless a majority of reviewers agree that the new S4s are any good, I would get new ones. So far, the S4 is beaten or on par with $35 headphones like the Soundmagic E30s.
For added bonus, the Gr07 if you have a bit more money, the Brainwavz B2 for $160 is also good (unfortunately we missed the sale at $130 with an amp), and the SE215 are praised around here.
