I've got a Giro Eclipse helmet to try. For the last few years I've had two helmets that I'd switch between - a Specialized Evade II (the older non MIPS version) for the winter and colder rides and a Giro Aether for the summer and warmer days.
The Specialized Evade II works well when it's cold and wet, the solid top of the helmet helping to keep the rain and snow out! and it also has fairly reasonable ventilation through the vents when travelling at speed. The magnetic buckle is nice too. The downside of that is I find it unbearably hot climbing at low speeds even in the spring. At 5mph there's no airflow through the front vents and the solid top of the helmet traps the heat inside.
The Giro Aether is a non aero helmet that has far more vents and is a good warm weather helmet for the summer. The Giro helmets suit a more rounded headshape, whilst Specialized helmets tend to suit more of an oval headshape.
The new Giro Eclipse helmet is marketed as an aero helmet that also has ventilation so I thought I'd get one to see what it's like. The problem with the marketing claims, particularly for cooling is that it's at a speed of 25mph. That high speed pushes more air through the vents of the helmet so the cooling claims for the helmet sound better than if it was done at a lower speed. I spend the vast majority of riding time at 15mph or slower.
You know that aero road helmet from Giro you might have spotted on the Pro Tour? It's here. Meet the Eclipse.
Fit wise the Eclipse is a lot like an Aether, suiting a round headshape. I've done two rides in it now, one at a temperature of +11c and one at a temperature of +15c. Riding along at 15mph or slower the main characteristics of the Eclipse helmet is air can be felt rushing in round the temples and along the side of the head, there's also noticeable air flowing around the back of the neck, but then there is also a big "deadspot" in the middle of the forehead, where there is no central vent and the middle of the helmet is blocked off. The Specialized Evade II doesn't have that deadspot at the front. Considering that blocked off section stands out at lower temperatures it seems like it could have the potential to get hot and unpleasant there on warmer days.
Climbing at low speeds, 5mph, it doesn't seem too bad so far. There are two big "chimney" vents on top of the helmet, and lots of side vents, so hot air shouldn't be trapped underneath hopefully.
Sunglasses wise I'm using Smith Pivlocks at the moment. It's possible to flip them up and stow them in the front vents of the helmet although they're maybe not as secure as in either the Specalized Evade II or Giro Aether because the vents are closer together.