I have it since pre-launch.
It's quite well done, big and serious MMO. The gameplay is similar to WoW but also different, which is one of the main reasons for people bitching and crying - they think it's wow with new skin or something and play it like wow and fail.
It IS brutal, there's shitloads of blood, there are naked girls and some of the quests are quite... unpure. (ex. there was 1 guy in a quest that kept the quest award in his ass, because he is a captive-slave).
There are tons of quests, and some "Destiny" quests which basically tell you the story and are tailored for each of the 4 arch-types. However, it's a real hack-n-slash so don't expect wonders in that aspect. I stopped reading the quest dialogs at about lvl 20(since then all quest gives are fully voiced bur). One bad thing is that ALL characters start in the exact same location, so if you decide to try a couple of classes before picking one for a longer run it gets very very boring to do them all over again.
All the classes are very interesting and well made, however there's huge balance problems still. They have a LOT of work to do, some classes are totally OP and others are worthless (pvp wise that is, in pve all classes perform about equally). What i really love about it is that they've taken the way of Vanguard making healers do DPS in order to heal, instead of being a healbot at the back of the party. For example, i play a bear shaman who is a "melee-healer" - they get up to medium armor and wield 2h blunt weapons. Also, 2 or 3 of their heals trigger only when the shaman fighting in melee. The other main heal heals in a small cone infront of the shaman. So in short you HAVE to be in the fight no matter your spec. The other two healers are "caster healers" where one's DPS spells augment his Heal spells and the being the opposite - the healing spells boost his DPS spells.
Also, every healer class has 2 HoTs and 1 direct heal at base and then others to unlock with talents. However the shaman for example doesn't have a single -targeted- heal - they all affect the whole party around the shaman or a cone infront of it. I am not sure about the rest, but i believe it's more or less the same. This might seem "lame" and "no-skill" since you don't need to switch targets etc, but in AoC healing is more about timing and rotation of your spells. Since you need to DPS in order to heal properly it would have been a mess to switch hostile and friendly targets all the time.
Two of the three tanks are hybrids too - The conqueror can't even wear a shield, he tanks with a 2h weapon or dual wield. And it works lol. Also they get 4 directional auras at a time(ex you put mana regen aura on your back, fire-dmg bonus on your both sides and armor bonus at the front), which are however quite weak for the moment The Dark Templar gets no 2h at all but he has various spells all based around life-drain so he can constantly heal the party a little bit. It's in no way sufficient to really heal but it's nice, somewhat like a constant healing totem from WOW and at times a bit more. The DT is -THE- pve monster for solo/leveling - basically no down-time, you go you kill you heal yourself while doing so...
Other than that, there's FUCKLOADS of bugs, but it's getting better and better since they are spawning patches like mad. Currently they've set up 2 days of the week for DT/Patch Days, so that means 2 patches per weak. They say later on when it's more balanced and fixed they will start releasing patches more rarely but making them bigger.
So in short, the game has a future, it will for sure not fail like Vanguard did. It's still full with bugs and needs major class-balance fixes for PvP but it's slowly getting done. It's nice to play as long as you don't run into nasty bugs, and it encourages team-play (there are LOADS of group quests).
Oh yeah, all the zones are "instanced" but they are huge and everyone can enter and leave. There's also the aspect of Guild Wars for instancing, where you have the same zone multiple times on a server, depending on the load of the zone. You can freely move between "instances" of a zone with a button in the interface. (Useful for escaping ganking retards 20 levels higher than you). Sometimes it's a bit confusing because the "local chat"(which i hate as a concept, btw) is global for all the instances of a zone, so when you group up with someone in the chat you then have to get to the same instance to play together. The limitation about instancing is, however, that you need to be 5 meters away maximum from a spawning point(think graveyard in wow) - you can't just "teleport" from everywhere.
I haven't seen end-game yet, i haven't had much time to play lately, so i can't comment on how it is. So far my guild has built 1 keep and are gathering resources for building other shit to protect the guild town.
ATM i can't decide weather i want to keep playing the shaman or play my ranger(who is still in newb town

).