Not a huge cost difference. A cheap 2m radio (~$80-$100) will net you most of the benefits. Oh it's more expensive, and yes you can spend more and get more (same goes for CB).
Substantially better clarity, even at close proximity, analagous to CD compared to cassette tape. No wait, even better. In fact no real clarity difference at 1 or 2 miles away either, it's as if they're still right behind you. This is probably the biggest "wheeling" benefit - trucks can be at opposite ends of a run and still communicate fine. example: Last year at CM our group on Kane creek got spread out, and I was able to talk to Dan the gunner just fine on 2m. No one with a CB from the "front group" was able to hear anyone in the "back group." We were up at that camp site where I like to eat lunch, just below the big obstacle on the shelf road.. and they were back just getting out of the weeds.. yeah that guy with the fancy ARB was slowing it all up
An almost infinite number of channels to select from, if "4" is busy for some reason.
Ability to tie into Colorado repeater system. Helpful if someone is late, and trying to reach the group. So you can be on Yankee Hill and still talk to someone in at their house in Highlands Ranch, or tell someone on I-70 where to turn.
one example: Last summer while we ran Jenny Creek, I was talking to Bruce who was running Spring Creek.
another example: Last summer, I was loading the truck in my driveway on Friday night preparing for the Ghost Town run camping trip, talking to the guys near A-Basin who were already there camping asking "what should I bring?"
Ability to contact someone in an emergency, even make emergency phone calls, when out of cell phone coverage areas.