I'm liking the turtle from this gen a LOT. Here's a movset I've been thinking of using. I have NO idea how good it will be, since I can't test it out yet.
Jolly
Sturdy
252Atk/252Spd/4 ???
Salac berry
Shell Smash
Aqua Jet/Waterfall
Crunch/Stone Edge/Earthquake
Crunch/Stone Edge/Earthquake
If you can guarantee the OHKO by the opponent and predict well, use Shell Smash to boost everything but defenses, which you wouldn't need at all on this set, and let the Salac berry activate. Now, you're running +4 (?) speed and +2 attack. If you feel you're not fast enough, or you need a move to pick stuff off, Aqua Jet is your choice, or Waterfall for more strength. The other two moves are thrown in based on preference and the rest of the team.