STAB is freakishly powerful, actually. Quite often, as a Grass-type, when given a choice between a Grass-type or a Normal-type attack against something like a Fire-type, I opt for the Grass-type attack. More often than not, I still see a higher damage number.
Now, throw in Adaptability... An Eevee I hatched, hovering around Lv40 now, can do more damage with tackles than my Lv74 Chikorita.
*In Mt. Bristle, 1F*
Escae, the Lv40 Eevee with 64 Attack, Tackles the random Spinarak for 138 damage. Escae then goes on to Tackle the local Doduo for 153 damage. Throw in a Machop, too! 157 damage against that one, as well! She's proving her strength already!
Meanwhile, a well-developed Lv74 Chikorita with 138 Sp.Atk sends a Magical Leaf to a Machop for 183 damage. The same Chikorita Tackles (
w/ 155 Attack) another two Machops for 145 and 139 damage. Even with a 34 level and a 91 Attack advantage, the Chikorita doesn't match Escae's damage potential, as far as Normal-type moves go.
Various "not very effective" Magical Leaf attempts at the local Doduo averages over 150 damage, higher than the normally effective Tackle, somewhere in the 140 range, even with higher Attack than Sp.Atk.
I say STAB exists in this game, and is often more prominent than even type-effectiveness. Anyone here feel like trying out more tests to be sure?
Be specific when titling topics.
This topic's title is: Specific. Sometimes, it's best to try it out. Still good to ask, though!