Without doing any math, I'd say the big difference between SB and Haste is SB only boosts offense while Haste also boosts your defense.

That said, don't underestimate the Wizard staples. If your melee options are already solid, consider picking up Hypnotic Pattern or Fireball so you have a ranged option that's strong against big groups.

Of course, you're a Wizard, so you can probably keep your options pretty open. Assuming a 16 Int, your preparations could look something like:

-Shield/Absorb Element/Magic Missile
-Misty Step/Shadow Blade
-[Fireball/Hypnotic Pattern]/Haste/Counterspell

This gives you excellent reactions in AE/Shield/Counterspell, a (near) guaranteed damage dealer in MM, one of the best panic buttons with Misty Step, a choice between blenderizing with Shadow Blade or the more balanced (offense/defense wise) Haste while also having a strong option against hordes.

Some might balk at preparing 3 3rd level spells at level 5, but they all cover very different scenarios. Counterspell is the least likely to be cast, but is incredibly powerful when it goes off, while Haste and HP/FB are both good in different scenarios.

If no one else in the party can cast Dispel Magic, I'd try to find room for that as well. Magic Missile, Shadow Blade or Haste being the easiest to drop for it. Much like Counterspell, it's rarely cast, but gamechanging when it comes into play.