As title are they any good as £75 seems a bit of value?

Yes, although there are a couple of models now. I've got the claimed 900 lumen version and it's excellent though very floody but it's perfect for a bar mounted light. I think there's a lower powered version now which didn't score well in the mag reviews

a mates got one – seems pretty good – decent beam, appears to be a bit better made than a bastid – certainly worth a go at £75

Owning the Bastid too, I'd say they're equal in terms of performance though the Airbike's battery lasts longer