I picked up some Westone 4's yesterday which I love and got a couple Westone 3's on sale that I am listing on eBay if family don't want them. It was a good sale so I took advantage.
I started considering based mainly on comfort selling my TF10 on head-fi and keeping one of the 3's. I had heard they were similar in sound sig at one point but I started reading and I don't know that it would be a smart move at this point.
See I have the 3's sitting in front of me in a sealed box. I don't want to open the box and then turn around and have to sell them on ebay and make the person think they are getting a used set of phones.
Like I said I am leaning toward just sticking with what I have but I would be interested in any helpful info from someone who preferably has or does own both IEMs.