@Huge, I know this thread is a couple months old, and I'm a relative new caver, but I can add a little bit of experience with my Petzl Vertex helmets.
I originally bought mine for multi-use, between caving, and woodcutting/tree work. I don't do a lot of tree work, but I like to have head/face/ear protection when doing so. So that meant a helmet that could accept attachments, and the Vertex has a range of ear/face protection attachments that are easily attached or unattached. If that's even a remote possibility for you, I would consider the Vertex.
Yes, I could concede without actually measuring it, that it seems a little larger than other helmets. If you do a lot of tight squeezes, maybe a smaller helmet and light combo would be better.
Hoever, regarding weight with a large caving light, I think the Vertex supports weight very comfortably. I wear mine this time of year for my mowing business, with a mesh-screen visor on the front, my Fenix HM65 head lamp, and the 3M ear-muffs, very comfortably. I think the adjustable headband, and straps across the back of the head/neck really aid with comfort, and supporting weight.
This past weekend during a vertical/ropes class, one of the instructors wore safety glasses, and commented how he likes to wear them for eye protection. He's not wrong, and I frequently wear safety glasses for work. The Vertex also accepts a flip-up half-visor, for mounted eye protection. I question weather this would work well in a cave, especially during tighter crawls, but I think I might purchase and try one anyway just for kicks.
I might suggest the Vertex-ANSI? version I believe, that is without the side vents. Unless your head/scalp sweat while caving that is. I like the idea of the solid, unvented sides, to keep the head a little drier from falling water or splashes.
They're about $100USD here in the states, so very competitive with other helmets. I recently purchased a "used"
(but still brand new in the box with plastic?) Vertex on eBay for around $55-60 after shipping.
BTW, my young daughter prefers a Petzl Borea
(I think these come in a "small" and "large" size,) to the smaller kids Picchu helmet. No way I would consider a Boreo/Borea in comparison to the Vertex. Not unless you wanted a minimalist helmet for tight squeezes. Which I think would best be paired with a smaller headlamp as well. Almost silly to pair a small, lightweight helmet with a big, heavy duty headlamp...
)
