By and large Carnac helmets are great.
I have four in total, a Bambino copy, an Evade copy, a full aero model, and a normal Notus.
However I do also own a Giro Synthe I keep for "best" and it has a number of features that just make it significantly more comfortable e.g. the cradle, the pads, the internal finishing. But that's a much, much more expensive helmet.
The fact they can knock out helmets for £10-20 makes a mockery of normal brands pricing, and means you can change regularly which I'm sure improves safety (and certainly smell!). I just wish they made something a little more premium, as I can't believe the small details on the Synthe that make so much difference would cost very much to add.