Some friends here in Texas have the Bontrager WaveCel and Smith Koroyd helmets. They're satisfied with them even in our summer heat, although most of them do more early morning rides which might influence their perceptions of ventilation. Although one fellow is in his 20s, pretty fit and fast and often rides 100-200 mile rides, and hasn't complained about heat in his WaveCel helmet.
I prefer better ventilated helmets but I tend to push a little harder and ride in midday heat. One of my helmets is a POC, which has thicker EPS foam than most helmets (and an overhanging brow that can hinder peripheral vision a bit when I'm in the drops). Ventilation is excellent -- it seems to aggressively scoop air across my head, better than my Bell helmets.
And the WaveCel and Koroyd helmets are a bit heavier. An old neck injury with permanent damage to my C1-C2 occasionally makes me sensitive to extra weight on my noggin, so over time I'm leaning toward lighter helmets. I used to mount video cameras on my helmets, but can't tolerate that weight anymore. Even the size large POC Omne Air Spin is a bit heavier than I'd like. A good commuter helmet for an upright bike, but I can feel the weight in my road bike position. I'm leaning more toward much lighter helmets like the Lazer. But there may be some safety sacrificed for comfort.