I rode a 200 km brevet in March, and forgot to put on sunscreen. Normally sunburn is not such a problem in winter, due to being covered up against the cold, but it was a warm day and I burned my arms and legs.
Yesterday, I rode a 300 km brevet, and packed some Coppertone Sport Sunscreen Stick that my wife bought me. It looks like a jumbo-size ChapStick. It's a solid, like ChapStick or a solid anti-perspirent. From the perspective of being able to leave it in a bike bag and not have to worry about it making a mess, it's a fantastic product.
Unfortunately, from the perspective of protection from sunburn, it's crap. Oh, it actually works, where you manage to apply it. But because it's a solid, it only protects exactly where you put it. It doesn't spread out and cover everywhere, like a liquid sunscreen or spray. So today I have pink tribal tattoos of sunburn all over my arms and legs, wherever I missed a spot.
I guess you could call this user error, but in practice people applying sunscreen in the middle of a long bike ride aren't sitting in front of a full-length mirror and being meticulous. We want to slather it on and get moving again. So I recommend avoiding this product and sticking with the traditional liquid version.
Though it might have some value, as a backup sunscreen that you leave in a bag (since you don't have to worry about it leaking) and use in emergencies, when you forgot to bring better sunscreen.