I can't claim to ever have worked with G10, so won't really speak on that one.
On the other three, you're looking at very similar materials, all impregnated in a synthetic resin(like stabilized wood, though the resins differ).
Thre three just end up with courser grain. Paper micarta is jsut that, paper soaked int he resin. Can get a nice polish out of it, some pieces show layers, others don't, have a knife right now that's getting bolsters from this material(probably). Just gives a nice shiney black accent to the bocote. But plain black, no pattern.
Linen micarta is made from fine cotton cloth impregnated in the resin. This gives soem mild texture to it(depending on how you finish it, and bead blasting can enhance the exture), and will also give a bit of definition to the layers often. A little courser than paper micarta, but still relatively smooth.
Canvas micarta is more cotton fabric, but noticably courser(though not actually canvas, to be technical). I like this for knives that need a good grip. Particularly useful, at least to me, for things like neck knives, as they need something that holds up well to sweat, etc, but also needs to offer a good, grippy texture, as the handles tend to be smaller than a fullsize knife, so you need more "grippiness" per square inch.
G10, as I've said, is something I've never actually worked with, but is a similar idea, except instead of using a natural figber, such as paper(wood) or cotton, it uses a synthetic fiber. Believe texture wise generally ends up somewhere around linen or canvas micarta, again, dpeending on how you choose to finish it.
ALl four are nasty to work with, though G10 particularly so(the resin makes them all nasty, G10 tends to be a bit worse, or so I've been lead to believe, due to the synthetic fibers in there too).
If you want, I'm sure someone here probalby has some little scraps of all of them, and could drop a little 1x1" or so rou8gh scrap in an envelope and send them yoru wya so you can see the differences. Would myself, but only have paper and linen micarta here now, not the other two.
Sure someone else will be able to help some more, but that coversmost of it.
Oh yeah, and paper micarta's easy to burn if your'e not careful(I haven't had as much trouble with that with the others).
Turns black micarta brown, and not sure what it does to other colors.
