I think the best corvette is the Sulturak (VR). The ability to inhibit shield regeneration is very nice, especially against advent. I've seen more and more players pick shield tech over hull/armor these days, which is why I prefer this one over the VL vette.
Probably the worst one is Shriken (TL). All the other vettes increases the survivability of your fleet in some way, by either decreasing enemy weapon effectiveness, or interfering with hull/shield/AM regen. This dumb vette does neither. It instead reduces movement speed? Really guys? I hope you realize that in a battle, the ships are staying still, right? So a debuff to movement is a trivial ability. I suggest a minor buff of some kind, like maybe a 25% increase in the time required to phase jump (stacks like the others). The ability is called disable engines, after all. This will also increase the viability of the overall TL faction, which is lackluster when compared to TR.
What do you guys think? Do you approve of my choices? If not, what are yours?