I’ve been using IE600s for a year and now generally happy with them. I too had issues with the stock cables cutting out, so replaced with 3rd party cables that work flawlessly. I also had issue with the provided tips being unable to find a reliable fit, so also replaced these with SpinFit W1s.
The SpinFits are a great fit for me but do make the IE600s brighter than the stock tips.
I am here reading this article as I am thinking of upgrading to the IE900s.