It kinda depends on how often you'll have to worry about sunlight. If that's not a huge issue, then IMO VGtM is the superior kobold, pack tactics is just too good. The tiny choice you get of ancestry doesn't compare IMO

Depends on how much you expect sunlight sensitivity. Pack Tactics doesn't interfere with action economy, so you retain full use of Cunning Action. This would probably be my choice for an Arcane Trickster, especially if your DM rules the +2/+1 treatment for it.

However, MotM offers a sorc cantrip (Booming Blade), which makes it a lucrative choice on any non-AT rogue to combo with CA disengage, or better yet Mobile or Rakish Audacity. The AoE advantage seems good on paper, but it's only great if you're going to have a party heavy on attack rolls (EB, Scorching Ray, Fighter, Ranger, Monk, etc).

All that said, races with sunlight sensitivity in a campaign will experience sunlight, which will feel pretty bad.

As others have said, Sunlight Sensitivity is probably the gamechanger here. If you're getting reliable advantage, that's huge, and if you aren't then you don't really get much from Volo's.

If you're locked to Scout, I think this provides a strong argument for Volo's kobold. The level 17 ability is very powerful, but locks down your build in a couple ways:

• Because you need to attack two different targets to get full Sneak Attack damage, you will almost always want to be building for ranged. This means that the sorcerer cantrip you get from Mordenkainen's kobold is just utility: you won't be able to use Booming Blade well, and Fire Bolt won't be as good as just taking a shot. It also means that Draconic Cry isn't very good, as you'd need to be within 10 feet of your enemies to use it.
• Because it takes up your bonus action, that means you're missing a reliable way to get Sneak Attack. Steady Aim would be fine on other ranged rogues, but it also uses your bonus action. Pack Tactics provides this quite easily off your frontliner, who will generally be within 5 feet of two enemies.

If you're planning a more melee-focused rogue, you probably want a different subclass.