Who could be a better Sweeper? Gardevoir or Scizor?

Question

I wanted to know because I have both of them in Pokémon Alpha Sapphire.
Scizor Moveset @ Scizorite:
Bullet Punch
X-Scissor
Swords Dance
Aerial Ace

Gardevoir Moveset @ Gardevoirite:
Moonblast
Thuderbolt
Psychic
Shadow Ball

Answer 1

With only those given movesets, go for Scizor. He has fewer weaknesses, more resistances, and a killer advantage with Swords Dance. For an in-game scenario such as this one, Scizor is the better option by a long shot.

Answer 2

It depends which side of physical or special you're looking for.

I found a lot of success in XY OU with Mega Scizor. I used this set:

Scizor (M) @ Scizorite
Ability: Technician
EVs: 216 HP / 96 Atk / 140 SpD / 56 Spe
Adamant Nature
- Bullet Punch
- Knock Off
- Swords Dance
- Roost

It gave Scizor very good coverage and bulk, as well as a form of recovery in case it racked up damage, and then swept with +6 Bullet Punch. It was a marvelous sight to behold.

Mega Gardevoir is typically used as a stallbreaker.

I'd say something like a set of this would work for it:

Gardevoir (F) @ Gardevoirite
Ability: Trace
EVs: 24 Def / 252 Spe / 232 SAtk
Timid Nature
- Hyper Voice
- Psyshock
- Taunt
- Focus Blast / Will-O-Wisp

The bread and butter of this set are Taunt and Hyper Voice, which rip through most stall teams with ease, preventing them from doing much in return to you. Pair with a cleric, and you can keep Gardevoir around for a lot longer.

Comments

He's talking about in-game. He won't have any kind of simple access to the vast majority of things you just suggested.