I also just got a pair (same seller?) as I was curious given how many people said this was an upgrade from the er-4. While it does not have the same sparkly and dry detail, the mids and bass wieght make this an easier pair to listen to for long periods. The soundstage seems more natural to me compared to the sterile er-4.
The best tips so far have to be these http://www.my-ear.com.tw/spinfit-tips/
Goes quite deep in and very comfortable. Just got to push the tips on tight as the first time it popped off in my ear and I had to get a tweezer to pull the tips out!
Is there a place that sells spinfit tips that ships internationally? I've been wanting to try those since I first heard about them.