Westone AC2 or Ultimate Ears 4 Pro

Not that this this has anything to do with the build quality of their customs, but the Triple.Fi 10s fit like a piece of garbage trying to be jammed into my ear canal.  Personally, i don't like being routed to a non-American support representative when i call a company who is supposedly only in existence to provide professional headphone solutions to the masses.  

I too was contemplating the AC2 until i heard it was only a single bore IEM.  Once i found that out i decided that the ES2 was better for me because I needed the clarity of dual bore on stage and wanted the extra bas response when I was listening to my own music collection.  Also, the ES2 comes in Kawasaki green, and that happens to be my favorite color.  

I can tell you that you will definitely experience top notch customer service if you go with Westone.  I have never once been underimpressed with their service, even after having nagged Rachelle nonstop for days about my order.  She was always helpful and never short tempered with me.  Hands down my first choice in the custom arena.  

Have you considered 1964ears? The triple driver looks to fit your budget, although the quads seem to have the extended deep textured bass people crave.

Did you ever make a decision? Personally, AC2 is going to sound darker after having demoed a few other Westone products.  Their low driver is strong, making their sound signature darker.  It's still very crisp in the highs, just maybe not as crisp as UE.