Troops types

Halberdiers: The cheapest troop type to make, Halberdiers have rather limited use as attackers, but can be used effectively in two ways. One, they are the ideal troop for attacking inactive players' cities. They carry more loot back that any other troop type and they are the second fastest troop type, so they can make quick trips and carry lots of rezources back. Two, they are the best troop for Explores/Searches of occupied wildlands. My experience has been that the most important factor in successful Explores/Searches is the time spent, not the number of troops or level of legend(s). Halberdiers are strongest vs. Charioteers, relatively speaking (they will still take severe losses against them.

Swordsmen: While tougher than Halberdiers, Swordsmen are in my opinion the most limited troop type. They are strongest vs. Archers and that is where there use lies. I use my Swordsmen for Defence only-putting a Seer in charge of them (Seers can hold more troops than other legend types). Occassionally I will use them for offensive purposes if I absolutely need to take out some Archers. While they are best vs. Archers, they are also the easiest for Archers to take out when invading Wildlands.

Archers: Archers are by far the best troop type; you would be absolutely fine just training Archers. Archers have first strike in any battle other than those against other Archers. If you have enought Archers you can wipe out the entire enemy army without taking a single loss. Ratios change depending on legend level, but typically a 1.75-1 edge vs. Halberdiers, a 3-1 edge vs. Swordsmen, and a 10-1 edge vs. Charioteers will be enought to eliminate the entire opposing army in one shot. Archers are strongest vs. Halberdiers.

Charioteers: The best troop type for defence, Charioteers are also the most expensive. Like I do with Swordsmen, I leave my Charioteers at home under the command of a Seer. When someone spies you and sees a ton of Charioteers are waiting for them tehy will choose an easier target. While they can deal out a ton of damage on offense, you are better off using Archers and not losing your Charioteers. If you are attacking an enemies City--Charioteers are a must. Charioteers are strongest vs. Swordsmen.

There are also other classes of troop, being Expert, Skilled, Master and then Elite/Heavenly, in order of ascending strength.
Expert troops can be trained in and defend Barbarian Famous City, or you can earn 500 Expert Swordsmen by exchanging an Expert Token.
Skilled troops can be trained in and defend a Shang Famous City, you cannot obtain them through any other way.
Master troops can be trained in and defend a Zhou Famous City, you cannot obtain them through any other way.
Elite/Heavenly troops CANNOT be obtained by a player. However, you may experience them on floors 7-12 of a Special Paradise. These troops are super human- be wary when attacking them.

If anyone has another use for any of these troop types, feel free to post below.