In my honest opinion, if you are new, base your choice primarily on your realm preference and narrow it down from there. Say Alb appeals to you most, then roll there and you have it down to 2 classes; Merc and Arms. Both are amazing in their own way.
Same can be said for other realms.
Feeling at home is the most important thing to get right at the start. You are going to be spending quite some time there if you intend on RvRing in the future.
My suggestion is to decide based on realm preference, unless you strongly gravitate towards a particular class or race design. Each of the classes described below is roughly on par with their rivals.
Berserker is the least defensive light tank, lacking the shield of a Blademaster or Mercenary. Its advantage is that vendo form offers guaranteed crits, with DPS temporarily surpassing all of the other classes; the tradeoff is that they lose the ability to parry or evade and will fall like a sack of bricks if focused.
Mercenary can use Dirty Tricks and win almost any 1v1 melee fight, or simply disable their target and move onto another threat. They are also surprisingly tanky with chain armor.
Blademaster retains its defenses at all times while still being able to elevate its DPS through triple wield. Zerkers lean more towards offense and mercenaries towards defense; BMs are a balance of both, though all three classes are decidedly offensive in nature.
Hero's Celtic Spear is a nightmare for enemy melees and anyone they're chasing. They can't be easily escaped, due to that back snare. Moose form is a powerful instant heal that will probably push them over the top in a fight, but the cooldown timer is long. Thrust is an ideal damage type against common targets.
Warrior has the highest weaponskill and doesn't sacrifice 1h weapon potential for 2h like Heroes and Armsmen. Sword/Hammer/Axe spec applies to both. This enables them to be extraordinarily versatile and defensive with high shield spec. They can either match peeling with hammer's Conquer back snare or go for sword's Ragnarok and cripple the enemy melee's swing speed.
Armsmen polearm styles are the best of any heavy or light tank. In a duel, their style reactive is devastating, and plate makes them passively tougher than warriors or heroes when wielding a 2h weapon. Their anytime snare is as obnoxious to escape as a hero's, and they can take their pick among all three damage types (requiring spec) while Hero must divert points into Large Weapons and Warrior has no access to thrust.
I'm really liking my Berserker now and will most likely take him to 50.
I'm fairly new to RVR, so I think it'll be a good class to learn fundamentals on.
Then in the future I think I'll play an Armsman because I really like Albion and they're fun to play as well.
You've chosen well for a beginner's character. Berserker is as simple as they come. That's important when you're lacking RvR instincts and must learn how to position yourself and who to attack. Fundamentals are quicker to grasp when not screwing around with weapon switching, slam duty, and guard. You see, you kill. Just avoid overextending alone, and set up keys to easily assist your melee train. Coordinated Mid trains overpower the enemy healers by stacking onto a target. Uncoordinated ones get picked apart.