From a control's player perspective which one do you prefer?
Spray kills scrounger for dead and is great vs gy decks, impulse does 3 damage very reliably (great for copter and a multitude of threats) and galv bombardement has the best late game potential (copies 3 and 4 are great).

3 toughness matters, Impulse.

I like shock

Fiery Impulse or Shock, depending on build

why shock? damage to walkers?

Bombardment/Magma spray are a bit too cute imo, for me if you're an aggressive deck you want shock, if you're more controlling you want impulse, it's just gonna be better a bigger % of the time.

Also occasionally reach. Hitting players/PWs is always beneficial

I haven't played control in awhile, but if I were playing it would be 100% Magma Spray to permanently deal with Scroungers, and whatever other graveyard creatures the new expansion has brought, like the black zombie one drop. But mostly it's for Scroungers.

But I don't know, maybe this new meta doesn't have people running scroungers? I've only been able to play for a couple of hours so far and maybe Fiery Impulse matters more. That would surprise me since scroungers seem like the bane of control and they've pretty reliably allowed me to beat those decks in the old meta at least.

Magma Spray exiles Scrounger. It wins. Include the others if your deck calls for.

Lots of things deal with Scrounger. I'm not changing my build and blanking on the hoardes of 3 toughness creature just to deal with Scrounger specifically.

I prefer bomb in decks that contain discard outlets. I've yet to build a deck where I really think I want shock. I wouldn't play spray, tbh. Impulse is best when the deck has a sufficiency of other spells, and probably best in general.

that very miuch depends on what you want the cards do. in my deck i wanted some permanent answers to not only scrounger, but things like haunted dead and prized amalgam. I chose a couple of magma spray.

I don't really think you want these cards to answer those copters on curve right?You need push, grasp, harnessed lightning for that job. I don't know why you want to run impulse or bombardment in a control deck today? They are not the efficient answers you want to draw in many situations. They were only good before kaladesh released.

seriously people are recommending shock to a control deck? and the reason is to ping down walker for 2 loyalty or for reach?

Magma Spray easily.

The amount of "things" that permanently deal with Scrounger on T1/2 while on the Draw is in what range? 2-4 cards? So by including 3 magma sprays you have to completely blank on the removal suite for 3+ toughness creatures. I'm not sure I understand how you build decks if including 3 cards means you can't deal with anything bigger than a 3/2.

x4 Galvanic Bombardment is the draw back of requiring you to run all 4 copies to be effective which limits the flexibility of your deck. Also, you MUST do 2 damage first, so unless you have a way to discard the 1st copy (Cathartic Reunion), then the 2nd, 3rd, and 4th can become "good" removal. I wouldn't necessarily play it just to deal with 5 toughness Vehicles...for that I'd rather have Lightning Axe + Fiery Temper.

x3 Fiery Impulse has the beauty of having a higher chance of dealing 3 dmg the 1st time. You don't need 4 copies for 3 copies seems fine. With 4 copies you can of course double up to kill something with 6 toughness.

x2 Magma Stray is better for control decks than Shock which is mainly only for aggro builds. I would stay at x1 or x2 Magma Spray as they're are really only 2 creatures in the format that destroy control decks (Scrapheap Scrounger).

So, if I were you and I were to build a Jeskai or UR control list for example, x3 Fiery Impulse + x1 Magma Spray w/ flashback or x3 Impulse + x2 Magma Spray without Jace would be a nice start. x1 Dispel or x1 Fragmentize seem cool in the main but those are mainly sideboard material.

So...x3 Fiery Impulse + x1 Magma Spray + Jace, Vryn's Prodigy (As the 4th Impulse or 2nd Magma Spray)