Can't compare 'em, cause I never tried the Artifact...
But I rode my brother's 152 WWW K2 for a week, and I liked it a zilion times more than what I expected from a board that costs about half of my old board.
Have to admit though, I've been out of the loop for a while, and my old board is a beat up camber deck with A LOT of milage...
Still, the only territory where the www let me down was fast icy runs, so it should be right up your alley. Buttery, flexible, pretty light...Seemed like the perfect park/jib board to me. From day one on the www I pulled off my usual lousy ground tricks near perfect, just because I'm used to a fairly stiff camber board instead of this butter stick.
Again though, to be honest: I'm no expert, and I've only used a handful of different boards in my life. You should really listen to someone who actually rode both boards instead of me
Don't know if there's anything similar to the LT skate banana that fits your buget, but it seems like that's still popular with the park/butter kids
For your needs I guess it'd make sense to go all the way with a hard rocker profile, right?