Check out my custom resource and review thread, I will be reviewing many custom IEMs in the next several months in various price ranges, although mostly the higher end. From what I currently have in hand, there is a difference when you move up in price. For example, the EM3 Pro outperformed the Fabs and Infinity X3 in most ways, although they all have different sound signatures. I actually think it makes sense to buy based on sound signatures, not just price/drivers, etc, which is one of the goals of my thread and my spending spree.
And on a side note, I know two people with the 1964-T and other higher cost customs and both say the higher cost customs are technically better. Plus, you can check out the multi-review thread by |joker| for a comparison of the 1964-T with universals.