Really digging this helmet. Needed to replace a different brand-and-model helmet that served me faithfully but had to be put out to pasture. Chose the Low Pro not only because it was triple-certified -- so I could be confident in the protection it offers -- but also because it was lighter and thinner and less Great Gazoo-like than anything else out there.
On fit: My head measured-in at 57cm, which is right on the border between the S/M and L/XL sizes. I decided to order the S/M, and when I first put it on I was all, "Boo, it fits too tightly, I made the wrong choice." But after some playing around with the fit adjustments it occurred to me to try lowering the back-fit pad slightly, so the thickest part of it ended up being tucked up under the ridge on the back of my head, rather than smooshing tightly against it. Now I was all, "Yay, it fits perfectly, I made the RIGHT choice!" After making that adjustment it fit like a completely different helmet -- so much so that I even had to switch to a thicker front-fit pad in order to snug it up a bit.
On customer service: Best experience I've had in a long time. Prompt and helpful answers to my many questions prior to buying...then immediate help correcting my mistake when I screwed up my order...then quick, hassle-free shipment...then more super-helpfulness when I had a followup question. Top-notch customer service all around.
Summary: First time dealing with Pro-Tec, and it's been a pleasure. The Low Pro Helmet looks sharp, fits (and can be made to fit) great, and has all the certifications to be able to claim that it will keep my noggin protected as well as it possibly can be. Stoked with my purchase.