It kind-of depends on who you wheel with. CBs have long been a staple in the offroad community, but walkie talkies, race radios and ham radio have been becoming more popular. Ill try to lay down a few basic points of interest.
neither of these four radios (CB, Walkie, 2-meter Ham, and Race) can talk to each other. your whole crew needs to pick a band (type and frequency) and stick with it for the trip. There is no radio that can handle all of these types.
As for quality, CB uses AM, Amplitude Modulation, while the others use FM. Just like the two radio station types, AM can reach further, but FM has better quality. This is further complicated by legal power output limits held by the FCC. Mountainous terrain further levels the playing field in terms of range.
As for popularity, CBs are popular with truckers, though, it has been getting quieter over the years, and some of those guys are downright rude. Race radios are popular with the professionals, and I see a lot of side-by-sides with headphones on (i wonder what they are listening to). Walkie talkies are cheap and easy in a pinch but arent the best in quality.
The last option is my favorite, Ham radio (Amateur radio, specifically 2-meter) requires a license, but its cheap and easy to acquire, and it opens a whole world of possibilities. I particularly like connecting to local repeaters and having the ability to talk around the world. Here in the Phoenix valley, there are a dozen repeaters, and there are people always on there having Nets (meetings over the radio) and Rag chewing (BSing), Theres even a morning quiz show that anyone can attend while stuck in traffic.
Ignoring all that fun stuff, Ham has a clearer voice and allows a much higher output power (Three orders of magnitude higher than CB!). Using simplex (basic 2-way radio setting) It is very easy to operate, just like all the others.
Final words: I carry a CB and a 2-meter radio, and this seems to cover all my uses.