I will help you with what I can, describing the different classes to you. Perhaps some of the info will help you decide, seeing what appeals to you.
The first advice I give is to not choose one class, but make a few alts. Play them all and see which ones you like. If you like more than one, you can play any class you like.
Another option, if you wanted to stick with one class but you get bored, is to make a hybrid class. This way you can do different play styles with one character.
That being said, here are my descriptions:
MELEE CLASSESMelee is where the “action” is. Weapons flailing, and bodies falling all around. It’s the most popular aspect of the game, and the majority of players are some kind of melee character.
Two Handed:
Two Handed characters are very good at melee. They have a good selection of weapons to choose from, and you can use a variety of builds and still be successful. For example, you can have a faster character with a fast weapon, a balanced character, a slow character with a slow powerful/crushthrough weapon….what they all have in common is that 2h weapons use nice in-game animations useful for cutting swaths through the enemy.
A downside of Two Handed might be that you have to learn to manual block pretty well in order to be effective. For newer players especially, taking on one opponent at a time can be a great challenge.
Some say that Two Handed characters are the best damage-dealing/dueling/Hero melee characters in the game.
Polearms:
Polearm characters can also be very good in melee. They can be compared to Two Handed characters in many ways (good damage, 2-slot weapons mostly, need to manual block well) but they are a little different. One advantage of polearms is the weapon selection is very varied. You can take some king of poleaxe and play like a Two Handed character, wading into melee. Or you can take a pike or long spear and play a support/anti-cav role. Or you can take a shield and spear and play as a hoplite.
With polearms you also must learn to manual block well, or die. Some polearms only have 2 attack directions, so its best to fight with your team if you’re using one of these.
Some say that Polearms are the most versatile class, and rival Two Handed characters in melee combat effectiveness.
One Hand/Shielder:
One Hand/Shield characters are invaluable on the battlefield. They are typically very survivable, able to defend against multiple opponents. They are also very useful for charging in to chokepoints or defending against ranged attacks. One does not have to learn how to manual block at first, which allows even newer players to be effective on the field. At the same time, taking on several opponents with skill allows experienced players to shine with this class as well. Each damage type (slash/blunt/pierce/shield-breaker) is well represented in the One Handed weapons, with several great weapons to choose from of each type.
The greatest disadvantage of a one hand/shield character is the reduced range and damage of the weapons. They are not as long or as damaging as 2h/pole weapons on average. Another disadvantage is that many shielders, since they have a shield, never learn how to manual block and become sitting ducks once the shield breaks. They also tend to be a bit slower than the other classes because of the shield weight.
Some may say that 1h/shield characters are the most durable and survivable characters.
RANGED CLASSESRanged characters can be a lot of fun to play. Nailing a long shot is very rewarding, and head-shots are exceedingly lethal. A good ranged character is a valuable asset to the team.
Archers have a good variety of bows and arrows to choose from, but only a few of those choices are viable on the battlefield. They shoot fast, and are great for taking out horses and lighter armored infantry. Bodkin arrows can be effective against heavier armor as well.
Crossbows shoot slower than bows, but the damage is much greater. There are less varieties of ammo to choose from, but they all deal pierce damage…so they can seriously wound even armored targets. They take a long time to reload.
Throwing weapons do a good amount of damage and have a fast rate of fire…but ammo and range are very limited. They are a good choice for a hybrid or skirmishing character, though many players have made a full time profession out of hurling axes and lances.
CAVALRY CLASSESYou need to have a lot of money to play a cavalry class. The upkeep for a horse can be quite costly.
Cav can be really fun though. You can zoom around the battlefield and do a great amount of damage….however since you are moving so fast people can deal greater damage to you as well. Cav can be very lethal, especially if the enemy is unaware of their approach. Also, they can make great support characters, bumping and trampling the enemy at the right moment that lets a teamie get the kill.
If you want to play a cav character, I recommend using a weapon type you like as a melee character. One Handed Cav, Two Handed Cav, and Polearm Cav are all viable options. Also, you will be de-horsed or dis-mounted often enough that you want to make sure you like the type of weapon you are using on foot as well as on horse.
The classes of mounted ranged: Horse Archer, Horse Crossbow, and Horse Thrower I am not too familiar with. These I would recommend for a more advanced player. Some call these the bane of C-RPG for their tendency to kite, run away, and delay the end of a round. However, they can be as rewarding and as useful as any other class if played with skill.
So yeah. I recommend alts and/or making a hybrid character.
Also, check the beginners guides section for builds and more detailed info.
Good luck!
Other players, feel free to correct or critique my summaries.
