Eventide Previews: Rock on

You see, the title is a pun.
The first official Eventide previews are coming up, and two of the cards are potentials for inclusion in Rock builds. Here you go:
As the article points out, this is a 4/4 for 4 mana, which is already pretty good in black, and solidly in Rock critter territory. However, I really, really like the added bonus of being able to knock of creatures if Ashling comes through unblocked. This can really halt an opponent’s offense, as they suddenly find themselves unable to play the tempo game with you, because they’ll lose their creatures on the crack back from you.
…and, of course, in Extended you can use Shizo to get Ashling through, free and clear.
On the other hand, we have this critter:
Classic Rock builds relied on Spiritmonger, a 6/6 for 5 mana, Regeneration, and a vampire-like tendency to get bigger. Eventide brings us in its place a 5/5 for 5 mana, with Trample, and the ability to regenerate twice, each time growing in the process. Not bad — but is it better than the Pro-black, 4/4, growing goodness that is Chameleon Colossus?