Thanks to their Regeneration upgrade that gives them +30HP and allows them to automatically recover their health over time, the Wookiees have the best Repeater Troopers in the game. They also have all trooper upgrades available. Their stats pretty much speak for themselves.
With so much DuraArmor, all ranged attacks dealing 8 damages or less (±bonuses), actually deal to the Wookiee Repeater Trooper only 1 damage. With that, consider their Regeneration ability giving them +30HP and you've got a very tough unit on the battlefield that recovers its health on its own. They're a unit of choice when playing as the Wookiees.
The Confederacy's unique technology, Droid Upgrade gives their RP a +25HP bonus, and +1 damage points. They are very strong, but definitely not as durable as the Wookiees'. It should be noted that they can't be healed by a medic: They must be repaired or garrisoned in order to heal.
3. Rebel Alliance
The Rebel Alliance's unique technology, Tougher Armor gives their RP a +30HP bonus. It's a good advantage, but it doesn't allow their Repeater Troopers to match the Wookiees' or the Confederacy's in terms of durability or strength.
Gungan's RP have a +1 range bonus thanks to their unique tech: Farseeing Binoculars. The rest of their stats are standard. With more range than any other Repeater Troopers, they can be quite powerful when combined with a Fambaa Shield Generator.
They have regular Repeater Troopers with all the upgrades, that can be produced 50% faster than any other civilization, thanks to their unique tech: Cloning.
6. Galactic Empire
Their Repeater Troopers have standard stats with no bonus.
7 . Trade Federation, Royal NabooTrade Federation and Royal Naboo do not have the Repeater Troopers upgrade.
I believe the Wookiees have the best Repeater Troopers in the game. The Confederacy and Rebels are pretty close behind, but the Wookiees still have the upper hand on this one. When teaming their RP with Berserkers, you can easily lay waste upon your enemies.