Please see this post by Kyle Horner and this one by Seraphina Brennan for their Aion impressions. Keep an eye out for future Aion content in their columns as well. This impressions piece will be written from my perspective.
I don't usually go for the style of graphics present in Aion but I've been pleasantly surprised so far. Cranking up the AA and AF smooths things out amazingly and turning on bloom effects gives the game a beautiful ethereal glow. Some of the texture maps are a little pixel-ridden when you zoom in close, but I think they're necessary to make the game run on a wide variety of systems.
Combat is great as a level 23 Assassin. I'm not simply mashing the same four buttons I would in most other MMOs. I have self-buffs, meaningful cooldowns, debuffing attacks, chain attacks, positional attacks, reactional attacks, and pattern attacks. What I like most is that combat feels situational. Sure, I have an ideal ability-cycle but very few fights go according to plan even against normal mobs so I'm constantly reacting.
I'll group animations and the world/ambiance together here. Aion's combat animations are possibly the best I've seen in an MMO. Even the emotes and idle animations are creative and fluid. The world seems to flow quite nicely and is richly detailed. I really like the attention to vertical space as well as the horizontal from what I've seen so far.
And what's all that vertical detail good for if you can't fly, right? I really enjoy flying and gliding in Aion and can't wait until I reach the Abyss where I can fully immerse myself in it. Flight provides another means of travel not found in many other MMOs and also adds another dimension to PvP.
It's not that I'm adverse to putting in effort to get something, but Aion's grind just seems like unnecessary punishment. I realize it's a PvPvE game, but I'm just astonished that they gate the PvP with 25 levels of bland PvE.
The first levels of your game are supposed to draw players in and make them feel a strong sense of progression, not send them running and screaming like Godzilla just attacked their city. The grind is even more pronounced because there's very little difference between each level (from 1-25 anyway).
At level 23 I'm still wielding level 19+2 weapons and 16+1 armor that's not much worse than the top level 23 stuff I can get crafted. It seems you only get new skills every third level too, which I also find strange. Why not spread them out?
I want to reiterate how bland PvE is from 1-25. Everyone has different tastes but I find Aion's PvE to be of WoW 1.0 caliber. There's been five years of innovation in PvE between WoW 1.0 and Aion, so I'm very disappointed that it isn't better. Most quests are either kill 10 rats, collect 10 rat tails, or deliver ten rat tails. Considering how boring and unrewarding the quests are, it's just more efficient to find an even-con spawn of squishies and let your eyes glaze over (i.e., grind). I also feel that the game is bereft of lowbie dungeons or instances. This doesn't really encourage grouping in the 1-25 game.
I'm putting PvP into the undecided category because I haven't experienced the Abyss yet. I've had a pretty good rift experience though. Basically, a full group of Elyos stormed into the area I was grinding in and I managed to sneak away undetected and sound the alarm. I joined up with a guild mate and three other random Asmodians engaged in area PvE. The Elyos were quite high level (most PvP rank 5) but this made them clumsy. They spread themselves too thin and we managed to kill two of them. We chased one more back to his two remaining comrades and had a rumble. We were really outgunned but a number of passing Asmodians helped out and we won the fight with few casualties. So far, this is my only real PvP experience, so I'll reserve judgment until I get more kills under my belt.
Client performance has also been a bit dodgy for me. It was great in closed and open beta but things seem to have declined since then. I've never crashed but the game hitches and rubber bands sporadically. I have a pretty decent machine fitted with a 9800GTX 512MB video card, which is way beyond the minimum specs as well as a solid cable connection, so I'm not sure what the problem could be. I've heard of issues with memory leaks, which could explain things, but I'll just wait it out and see how it goes. It's not like a bit of lag makes my grind sessions unplayable... It will only become a major issue if it persists through the Abyss.
Overall, I'm mixed in my feelings about Aion. I'm not the biggest PvE fan to begin with, so the fact that Aion's PvE is so bland makes me even less of a fan. I am a PvP junkie though and experiencing the game's combat in the Abyss could be immensely fun. I'm basically going to keep ploughing ahead until I get my first few licks of real PvP and then re-evaluate the situation.
Many players say the game really comes into itself once you hit level 25. While I'm a bit confused as to why NCsoft would design an MMO in such a way, I'm willing to risk it given that I only have two more levels to go.