I did a search and only found 1 solid, in-depth "vs" review of the ES5. Markl, I believe, found them to be quite a step up from the PX200. Considering it's double the price, I would hope so. He also indicated that it had superior build quality, which is of particular interest to me, but he didn't really discuss the wiring and insulation. That's the PX200's big weak point, in my opinion (not the frame), so here's hoping that the ES5's wiring is more durable!