I've spent a couple hours digging into this here. Lots of info that has been very helpful, but I'm hoping someone has direct advise based on my situation. I've decided to have some custom fit ears made. I've been using Westone UM2's for a while with their comfy tip, and I'm MORE than satisfied with their tone and performance. I'm not really looking for an upgrade in that department. What I want is similar performance in a custom fit so that they are easier to take in and out. It takes a bit more time to compress the comfy tips and slide them in, and they do get dirty and have to be constantly replaced which is just getting old. I have considered the UM56 custom tip, but I've read a lot of people say how it increases the chance of breaking the tip off the UM2. It seems a lot of folks have complained of this also. So, I'm thinking of the Westone ES2 which seems to be billed as the same "technology" used in the UM2 and vice versa. Can anyone comment on these two by comparison? I'm looking at Ultimate Ears 4, which seems to be roughly comparable to the UM2 in terms of component quality. I really like the look of the UE4, but not having tried any of their products, I'm a bit scared of going a completely different direction when I've been so satisfied with my UM2's. Thanks!