A great game that adds much needed improvements to the MMO experience, but still suffers from it's own issues.
The biggest improvements are in terms of the combat system. There really is no comparison here to previous MMOs, the combat is leaps and bounds more enjoyable than anything previous. In WoW style combat systems you simply stand around and wait for attacks to hit or not based on ability scores. In GW2 if you stand around and fail to dodge or evade you will get owned. You are constantly moving and dodging and abilities actually feel meaningful. You need to chose your utilities carefully and employ them tactically. Firing off everything in one burst is not viable as you will leave yourself vulnerable to your opponents in both PvE and PvP. You learn to use interrupts and counters effectively to maximize your effectiveness. There really is no going back to WoW style combat for me at this point. It just feels shallow and boring in comparison.
Leveling and questing is also improved. Each zone is filled with Renown Hearts, which are areas where NPC give you a variety of task to perform to build up renown until they become completed. These typically unlock vendor NPCs that sell useful upgrades and crafting materials. Each zone is also filled with dynamics events that trigger based on your actions and many of which can spawn even more events based on whether or not they are completed leading to a huge variety of things to do in any given zone. Dynamic events also reward karma currency, which can be used to purchase new weapons and armor. It is entirely possible to level just doing renown hearts, just doing events, or even just PvPing so no one is really forced to do activities they don't enjoy. Crafting rewards significant amounts of XP as well and leveling crafting from 1-400 rewards 10 lvls per crafting skill.
All of the different classes (professions in gW2) also feel dynamic and no two play exactly the same. While there are similarities in playstyle say between engineer and elementalist, none of them play exactly the same. There is enough variety in abilities that most professions have multiple viable builds and counters available. And you have multiple weapon sets that have their own abilities as well as utility skills that can be swapped out of combat you can change your abilities on-the-fly.
Now, not everything in sunshine and rainbows, however. There are some serious issues presently in bugged traits and abilities that cause them either not to work, not to do what the tooltip says, be completely non-functional, or actually function to reduce your effectiveness. Some classes such as necromancers and ranger have far more bugs than other classes as well. So there is currently an imbalance between design intent for a class and what they can actually do. This wouldn't be such a big problem if the bugs were being fixed, but many of them have been present since the beta and very few have been addressed since launch. Not to mention there has been little to no communication on this from the devs. There are also severe imbalances in WvW due to what I would consider rampant exploiting (exploiting stealth, exploiting visual bugs, fly-hacking, bugging orb bonuses, the list goes on...). Far more than I have ever seen in most other MMOs and again these are not being addressed in a timely manner. Botting is also a huge issue, you will often see armies of bots in high level zones farming spawns and events and generally making it difficult for real players to complete events.
Pros:
-Dynamic combat is leaps and bounds beyond most other MMOs and is much more enjoyable.
-Stable - I could count on 1 hand the number of crashes I have had in 300+ hours of playtime.
-Great variety in playstyle between classes.
-Graphics are quite good and the artsyle is IMO way better than WoW. Huge variety in terms of character customization during creation.
-Sylvari are the most interesting and unique fantasy race out of any fantasy MMO.
-Crafting is well implemented and easy to manage once you get the hang of it. The Mystic Forge allows the creation of some very impressive and useful items.
-Transmute stones function much like transmog in WoW allowing you to change your armor and weapon skins to anything you want and still have the stats you need.
-All top tier weapons and armor have the same number of stat points so there is no gear imbalance between players in high end gear.
-Dungeons are challenging, but fun. Some could use some tweaking, but overall I enjoyed both the story-modes and the exploration modes.
-Lots of ways to level - crafting, renown, events, structured PvP, and WvW.
-WvWvW battles are really fun when working properly and provide bonuses for the whole server, which encourages participation.
Cons:
-Lots of bugged abilities and traits. ANet has been very slow to respond and slow to fix these bugs. Some classes are much more heavily effected by this than others, which is leading to them not being played.
-Rampant exploiting In WvW which significantly detracts form enjoyment (see examples above).
-Several classes are much easier to play effectively and be successful in PvP, again leading to over- and under-population issues.
-Bots are running rampant in high level zones and are not being removed. Again this problem has been around for months and not being addressed adequately.
-End game is fairly limited. It mainly revolves around sPvP, WvW, and dungeon/event running in PvE. This is a design intent on the part of ANet and it is debatable as to whether or not this is a con.
-Biggest con is failure of ANet to address bugs, hacking, botting, etc in a timely manner. Hacking in WvW is still rampant, severe bugs have been around since early betas, and bots are running rampant in end-game.
Conclusion:
GW2 is an amazing game with a great atmosphere, great visuals, good story, and excellent gameplay. However, the number of bugs and issues that have been cropping up and and not being fixed are starting to detract from my play experience. ANet has a real gem on their hands here, which is the first game IMO that could rival WoW, but unless they start pumping more resources into correcting the know issues people are going to start to get fed up. A month ago I would have given this game a 9+, but as of now I have reached lvl80 on two characters and played them for significant periods of time the holes in the screen are starting to show. If ANet can effectively address these issues in a more timely manner this game has nowhere to go, but up. However, if it continues along it's current path of poor communication and inability to fix issues they may have a serious problem. Only time will tell, but seeing as I have gotten more than 300 hours of enjoyment out of the game I can highly recommend it if you like MMOs.