IMHO Archen (Aaken) should be top tier - When you get it, it's roughly the same level as your pokemon, or slightly under, but even then it's a powerful pokemon in it's own right. However, as soon as you evolve it, it turns into a lightning fast killing machine OHKOing stuff like nobody's business, definitely a great pokemon.
Its ability is a draw back though. I think its called 'Faint Hearted'? Anyway once Aaken or Archeops drops below half health their sweeping power is gone! Could be annoying if your doing a few battles on the trot without healing items, which I tend to do alot on single player.
I tossed a coin to choose my starter, If heads it would be Oshawott, Tails Snivy, and if it landed on its side Tepig lol. Anyway the coin chose Oshawott.
Also its only one more day till the UK release! Hooray!