I like the FRP panels, but when you add the cost of the troweled-on adhesive (applied with a notched trowel), it's a bit pricey. I would not recommend applying adhesive with a caulk gun in the garage. You want a solid even backing so the FRP doesn't crack or tear if you smack it in a place that doesn't have continuous support behind it.
I'm remodelling a very abused garage in my new-to-me home. Previous owner pretty much destroyed all of the finish work. For example, all of the drywall joints have failed due to him venting a gas dryer into the garage, hacking up some framing, hanging very heavy lights with toggle bolts (pulled the drywall off the ceiling), etc. I'm in a huge rush to get some things done before winter hits, so I've taken very few pictures. But I did snap one right after I installed the first two pieces of FRP. Since that time, I changed my mind and am putting some above the first and reinstalling the FastTrack for my yard tools. Normally this track is completely full (and it's one of several I'm installing), I just put two tools up there for the picture.
I do really like it; it's durable and VERY easy to clean. It's also reasonably resistant to chemicals, which is nice for fuel and oil cans and gas-powered yard tools. It'll also tolerate some degree of flying sparks from a chop saw or grinder (I can't say yet how well it'll handle welding splatter). So if you find the cost prohibitive, just use it selectively. I _could_ do the whole garage floor to ceiling, but there would be little point in my case since I'm putting slatwall and stainless steel pegboard in many areas. Like you, my garage is mainly for car work. No tool cabinets or benches along the side walls so I can get 4 cars in it (4 car garage) and still open the doors and accomodate a lift. Hence the side walls are getting FastTrack, slatwall and pegboard to hang things that don't protrude too far.
Be aware that most studfinders don't work well (if at all) through the FRP and adhesive. If you expect to mount things over the FRP later, you'll want to mark the stud locations in a manner that lets you find them without hunting after the FRP is installed. Exploratory holes in drywall are trivial to patch to invisibility, the same is not true of holes in the FRP panels. I'm installing FRP behind my VIM air tool racks so I don't trash the drywall with grinders, air saws, air chisels, impact wrenches, etc. Have to mark things first so I can hit studs with the lag screws for the air tool racks on the first try.
I use DAP 3.0 window caulk (clear) to seal the FRP panels in their trim (cap, panel-joining and corner) and also to seal the trim to the wall. It will last a very long time in a garage.
A big advantage to drywall is that it's easy to patch and it's inexpensive. If you put some sort of transition at say 4 or 5 feet up on the wall (chair rail, whatever), you can patch and paint the lower portion once in a while without having to repaint the whole wall and deal with cutting in paint at the ceiling. Just a thought. I like the FRP panels in select locations where I know drywall would look like hell in no time at all, for the rest I'm OK with drywall and a good primer (Zinsser B-I-N if you can afford it, or Kilz Original or some other oil-based) and paint.
