I have worn Giro helmets exclusively for years for both my mountain and road bike needs. Size medium always fits me well. Fit, quality and features on the Giro Manifest are top notch as I would expect. Taking advantage of the great sale price was the tipping point in going with the top of the line.
I've owned the road version of Giro's spherical MIPS helmet, the Aether for the last two years and I love it. So as soon as this version for Mountain Biking came out I really wanted it!
It's very comfortable not having any of the MIPS plastic against your scalp but still having the safety benefits of MIPS. It's also very light weight, and the fit is perfect. I have a more oval head, most helmets sit a bit high above my ears, but this one comes down perfectly, a quarter inch above my ear, and just above my eye brows. It also covers the back of my head nicely.
The vents are quite generous, I'll be happy to have that ventilation on the warm days! It's worth mentioning too that the colors are way better in person. The matte gray has a slight bit of blue to it and the lower portion is kind of marble like. Very nice looking!
I found that the manifest is one of the most ventilated mountain bike helmets i have ever used. And the retention system is very comfortable, even on very long rides. The only downside is that it rides very low on my brow, and pushes my glasses down my nose, (it is only noticeable with big sunglasses, but nowadays, it seems like every brand is going for the biggest ones they can fit on your face)even adjusting the retention straps to it's higher setting.
Needed a road helmet update, and wanted a little more head coverage, which the Manifest provides ... closer to the ears and more around back. Easily removed the visor, and had to sand, very slightly, several of the many foam nubs inside that were a little too aggressive against my head. Angle of the chin straps allows wearing glasses without strap interference. Have used Bell helmets previously, and this Giro fits fine too. The chin strap magnetic catch is different and takes a little getting used to.
I replaced my previous helmet w the Manifest looking for the best possible protection. I recently experienced the most violent wreck I have had. OTB over the bars at speed w head first impact. I have no recollection of it, but my buddy watched it happen. CT scan shows no brain damage and I'm feeling pretty good with all things considered. Thank you Giro for saving my bacon !!!