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Hope's biggest disadvantage as a Commando is his low strength stat, but then, he gets Ruin right away so that shouldn't be a big issue. In fact, Commando can be very effective for Hope against enemies that are weak against Magic but resist most Elements. He lacks many auto Abilities, notably including Launch, making him a poor choice as your lone Commando, but then, you're not likely to use him in that Role.
Sazh is an interesting Commando because of his two pistols. Each shot does less damage than other Commandos, but he gets twice as many, and they seem to build chains slightly faster as well. His Random: Instant Chain Ability also seems more likely to go off. (As you can see, I have a lot of certainty about these things...) Sazh's biggest advantage is his Blitz attack, which hits many times over a very wide area. However, he lacks some of the basic attack enhancing Abilities, such as Ravage and Blindside, and is the only one of the four Characters with Commando as a primary Role that lacks the Launch ability. Against any enemy where Launch is vital, such as Behemoths, this basically means Sazh can't be your lone Commando.
As Commandos go, Snow is pretty effective, lacking only the Lifesiphon and Faultsiphon Abilities. It can be difficult to actually use him as a Commando much earlier in the game, since he's so effective as a Sentinel, but he'll get the job done. His Sovereign Fist Ability clears the chain gauge and deals massive damage, so it's best used near the end of an enemy's stagger period (and preferably with a Genji Glove equipped).
Vanille is the most limited Commando in the game (and has the silliest Weapon), lacking both Launch and Blitz. She does get Blindside and Faultsiphon, auto Abilities that are easy to take advantage of. However, her Role should generally be limited to that of a secondary Commando. She's more useful for the Augmented Attack effect than actual Commando Abilities.
Bonus Type
Augmented Attacks