Troops quality

there are 3 kinds of troops quality

Regular
troops that fall in this bracket are by example line infantry, not referring to the unit type, but to the troop itself that is called line infantry, simple units that every nation can train in their barracks/stable/artillery depot, they often have very, very low stats compared to premium troops, but they can serve as cheap cannon fooder if you have spare deployment points

National
national troops are those that can only be trained by a specific nation, unless you paid science to level them up (not recommended if you play in kongregate.com not sure at Facebook) their stats are exactly the same, but they can be trained by you, the difference is the men per regiment, by example, while premium imperial guardsman has 36 men the national imperial guard, trained by French empire, has 26 men, or while premium black hussars have 12 men the national black hussars trained by Kingdom of Prussia have 8 men

Premium
this kind of troops are the best troops in the game they have high stats (same than national but higher men-per-regiment) and one thing that distinguishes this kind of units from the rest is that they dont take any dwelling space, you can have a thousand of them without extra dwelling space, the gap between national, premium troops and regular troops is HUGE and unless you outnumber the enemy by a lot people should not even try to use regular troops against premium or nationals

Seargent
the seargent troops are like the premium troops, with the difference of improved statistics, it may be anything, more ammunition, accuracy, health, range, etc, many of them can be got in your clan shop using diamonds, or using gold, altrought it is not recommended because of the expensiveness (IN GOLD) in some situations it may be useful, this troops should be used on hard battles where you have limited deployment points, they are rarer than premium troops, but they are more useful

Veteran
Recently a new type of troops have been added, the Veteran troops, this troops have huge stats changes and in some troops it even changes the way they should be used, veteran troops can have a change in every stat, and one of the changes may include deployment points, the changes are very noticeable and they have 3 perks instead of the regular two, they might be got mainly from clan wars, getting a province, and then you will get some of them, plus one per day for free (along with the other stuff) and the ability to buy them for diamonds in diplomatic center (altrought its not recommended because its somewhat expensive)