I think Absol is generally the preferred one. Great early hand disruption allows you time to set up while hindering your opponent's chances of setting up. Then once your initial Absol is KOed (or you Retreat it), just abuse Gallade and Gardevoir to no end.
Absol version:
I start with a Ralts. Uh oh, now what? I'm a turn behind in discarding trainers, and that's enough for Rare Candy + Stage 2, or some crazy draw card.
Or what about lone Absol starts? What does that do, when your opponent goes "Okay, I have Magmar active. Attach fire energy. Boom, 20. You didn't discard Magmortar? Play it. Play a fire. If I show a strength charm to you, you lose. Ya know that, right?"
What about Lone Stantler? You could have found a Holon Mentor by now. :/
Lone Sentret? You're drawing extra cards and
hopefully found SOMETHING by now (since Sentret DOES give you an extra card each turn with Grope). Even if you have only Furret, you can evolve and have enough HP for Magmortar to need some more energy to KO you (still REALLY bad, but not terrible).
There's a lot that can go wrong with Absol, plenty to go wrong with Furret, but not a whole lot that Stantler can do that's bad for you. :/ Heck, even Phione can go horridly wrong if you only have Phione and go first.