MTG Salvation

Mostly I'm looking for what would be a better fit for my deck between Quicksilver Amulet and Cryptic Gateway. But, with all the choices of Beasts and support out there, any general opinions on where I could steer the deck are certainly appreciated.

Deck:

Creatures:
4 Arbor Elf
3 Arboreal Grazer
3 Kalonian Tusker
3 Krosan Warchief
3 Leatherback Baloth
2 Ravenous Baloth
3 Elder Gargaroth
3 Garruk's Packleader
2 Thragtusk
1 Rampaging Baloths

Enchantment:
4 Wild Growth

Instant:
3 Beast Within

Plainswalker:
2 Garruk Wildspeaker

Artifact:
2 Quicksilver Amulet
or
2 Cryptic Gateway

Land:
2 Contested Cliffs
4 Fire-Lit Thicket
4 Rootbound Crag
12 Forest

I do worry, beyond the Arbor Elf and Wild Growth, that things are going to be too slow. Even for my casual games.