While trying not to sound biased - Marco is a really strong unit. While his Captain Effect will likely not see play on a day-to-day basis - His stats are great for a PSY Unit and will almost find a guaranteed place in anybody's PSY Team. 

If that wasn't enough - Marco's Special that will heal all damage done meaning that you can tank hits and stall more efficiently. He will solidify the PSY's position as the ultimate sustainable team. 

His flaws are plain and simple - His Leader Skill will likely not see much play aside from a full-1 Turn Burst combo. 

Diamond Jozu

QCK Fighter

Colour	Type	Rarity	Health	Attack	Recovery
QCK	Fighter	4/5 Stars	3,300	987	231

Captain Effect	All QCK Units gain 2x HP/ATK
Special Move (15 Turns - MAX 8 Turns	For 1 Turn, Nullify ALL DEX Attacks

Another QCK Leader for those that want a QCK Team and can't pull an Ace. This guy can nullify DEX attacks which is extremely useful when facing Bosses like Mihawk and Doflamingo (in the future).

Jozu may not be the flashiest or the most exciting of units in terms of stats, but he's definitely Tier-1 Material with a great special that will only mean more and more in the coming future.

You could almost say Jozu is a Support Lead due to his low ATK and Special and thus running 2 Jozu as Leaders can lower your damage slightly compared to the Ace team counterparts. You will often find Jozu running around as a crew-member in multi-coloured teams.

"Flower Sword" Gran Vista

INT Slasher

Colour	Type	Rarity	Health	Attack	Recovery
INT	Slasher	4/5 Stars	2,840	1,325	185

Captain Effect	All INT Units gain 2x HP/ATK
Special Move (15 Turns - MAX 10 Turns	Deal 5000 Fixed Damage to all enemies

Another INT Slasher that will bring the competition to Mr. 3. You will find Gran Vista used fairly regularly in both INT and Slasher Teams with his incredibly high ATK stat at 1,325. 

Like all Slashers, Vista is a monster when it comes to Stats. He doesn't bring much utility to the table except for his Fixed damage for killing high defence enemies like Crabs. However under Mihawk's command, this guy will whitewash crabs with or without his Special.

His Captain Skill is the fabled 2x HP/ATK Ability like Asura Zolo. To INT Units, this skill is often seen as a great alternative to Towel Nami leads. Running double Vista is fairly common in JPN and is more preferred generally for the secured victory.

Izo of the Shotgun

DEX Shooter

Colour	Type	Rarity	Health	Attack	Recovery
DEX	Shooter	4/5 Stars	2,550	1,068	319

Captain Effect	DEX Units gain 2x ATK/Recovery
Special Move (20 Turns - MAX 10 Turns	Convert all [STR] and [QCK] Orbs to [DEX] Orbs

An Orb-Manipulator for DEX Teams - Izo can change 2 Orbs into the oh-so desired DEX Orbs. With fairly solid stats - Izo will be seen in a couple DEX Teams as a prime Orb Manipulator.

Flexibility-wise, Izo is not the best. Any Shooter Character will have to suffer for a long time to come which means this Whitebeard Commander can only find home in DEX Teams. That being said - Izo is a solid addition to any/all DEX Teams and should not be underestimated.

As a Captain, Izo will not be as good as Ashura Zoro (a Free-Unit) so odds are you won't likely see this Commander on your Friend List on a regular/common basis.

Blamenco of the Otsuchi

STR Striker

Colour	Type	Rarity	Health	Attack	Recovery
STR	Striker	4/5 Stars	2,488	1,252	268

Captain Effect	STR Units gain 2x ATK/Recovery
Special Move (20 Turns - MAX 10 Turns	Convert all [DEX] and [QCK] Orbs to [STR] Orbs

Blamenco is similar to "Izo of the Shotgun" - he will convert 2 Orbs into the STR Team's dream orb. He has strong stat with a high ATK at 1,252 making him a must-include in pure STR Teams.

Flexibility-wise, Striker units are lacking their precious leader so you will have to wait for that. Otherwise, Blamenco will join up STR Teams as a Orb Convertor/Hard-Hitter due to his high stats.

As a Captain, Blamenco outclasses all other STR ATK-Boosting Captains mainly due to that 2x Recovery addition. As such, Blamenco should be used a STR Captains taking over from Mr. 5/Monkey D. Luffy (Gear 2).

Whitebeard 

STR Striker

Colour	Type	Rarity	Health	Attack	Recovery
STR	Striker	5/6 Stars	3,900	1,360	235

Captain Effect	While your HP is 30% or below, All Units gain 3x ATK
Special Move  (25 Turns - MAX 17 Turns)	Reduce all enemies' current health by 30%

The World's Strongest Man arrives as the first 6-Star Unit in the game. He boasts a monstrous 3x ATK boost to all allies regardless of their colour or type - at a small risk. He has incredible stats that overall cannot be triumphed currently.

Considered the Strongest Lead currently in JPN - His damage output is higher than any other team including Monkey D. Luffy: Gear 3. He has high stats that tower over most units except Arlong in attack (for some reason). If that wasn't enough, Whitebeard has a nice 30% health reduction meaning with double Specials - the enemy will drop from 100% to 49% Health. This simply just means easy clean-up for the win.

His flaws is... the 30% Health requirement. Being on low health will mean you are at risk for getting knocked out of the competition if you are not careful with pre-emptive attacks. Thus doing proper homework as well as using units such as Hammer Usopp will be vital to maximize the usage of this Beast.