I've owned the Ecrin roc for 18 years, a vertex for about 4 years and lately, I've purchased a Petzl Altios.
It has turned out to be a fantastic helmet, I just can't say enough about it. It's very similar in design to the Elios, but differs in the added mesh suspension, which levitates the helmet off your head. It's the most extraordinarily comfortable helmet I've ever put on and I'm glad to recommend it as the best helmet out there for caving. It's so light; you almost can't tell it's there.
I found the Ecrin to be a great helmet for caving and would buy another one if the Altios wasn't as superior as it is. I originally bought the Vertex thinking it would be a great caving helmet, but my final opinion now is that it is too heavy to be good for caving. The headband doesn't seem to tighten down very much and it was always falling forward over my eyes in a crawlway, so I I no longer use it. It is great for rope access and rappelling outdoors.