All monkeys are horrible. They learn Acrobatics (their only, or one of two decent attacks) at late lv 31 when everything in wild grass one/two shots them.
Sandile has Bite when you catch it, you get Dig and Rock Tomb at that time too. Sandile also learns Crunch just before evolving. Scraggy is slow and has to wait till 39 for evolution. I think Sandile is better in-game.
That's true, Blitzle is better vs Elesa (Sandile dies too fast to Flying attacks and Rock Tomb has shaky accuracy) but fails to be really useful after Skyla.
Agree with Stoutland being great, very solid mon. His Return is strong because you train him since lv 2-4.