Are they better than budget ones?
Lighter, better vented, but ultimately only been through the same testing.
not sure about lighter.
They go faster. Its a fact. There's no actual science behind it. But it is a fact.
There was a which report on helmets. Most of them passed the CE tests, but they ran some slightly more hardcore testing (simulating whacking it against a kerb I think it was), and some of the really cheap like £10 ones actually failed that, whereas the £30 ones were fine. So really really cheap helmets might not be as good.
Since no one really knows and the difference might be only £60 for a one time purchase why would you take a chance with the cheap helmet?
The Poc Trabec is costly but it is designed with additional reinforcement that means it can take more than one impact before it needs replacing. I'm not sure of how that is specifically designated but I had a small off in mine the other day and gave the back of my head a reasonable clank. The polystyrene is fine and there is a tiny indent in the plastic shell. I think in any other helmet I would feel the need to replace it.