Because of server issues on Friday and still here and there some heavy lag issues (go into a fight, suddenly game stucks for several seconds and when it finally reacts again you are dead) on Saturday and Sunday I couldn't play too much. I reached level 7 or 8 with my Elementalist and also tried to play a Guardian up to level 3 or 4 I think.
I felt a bit lost in the game, since there was no tutorial. I am pretty sure they will add that before release of the game, as it was like that in GW1. Nowhere was described how the skill system works, I didn't find out where I can craft something with my crafting material I found tons of or where I can learn a job like cooking. I also didn't find out what the class teachers are good for. Somehow I also didn't know how I can write in team chat (I tried to write "/team hello" but that didn't work). And several little stuff.
The game itself didn't feel any like Guild Wars 1, but that was to be expected from what I heard before. It felt more like World of Warcraft and other MMORPGs. I only tried the PvE yet though, I have hopes that the PvP system will be great as it was in Guild Wars 1, although I heard a lot of negative comments about it so far, but I guess people need to learn the game first before judging a lot about PvP. And I wouldn't be surprised if they still add additional PvP modes, it was like that in GW1.
In PvE I liked the fact that you don't stand still and smash only buttons but that you have to move also. Especially when you are fighting in melee, you have to walk up to your enemy on your own and face him correctly, and since the enemy might move too you have to keep following him. As an Elementalist you are able to cast all your spells while moving, which is different to other RPGs. This adds some more action to the game. The dodging system I didn't get through yet, in the early levels there didn't seem much reason to dodge yet though, but I bet it will become important later on. In the mess of the overcrowded places it was hard to stay on top of things also. Great were also most of the AoE spells; in Guild Wars 1 they were always automatically cast on the target that you selected, and since most of them would move most AoE attacks would miss and be useless. But here you can choose your target for your AoE spells manually and anticipate where enemies will move into so that you will hit and deal great damage.
The quest system I don't know how to feel about yet. You don't have to talk to the quest npc anymore but just come near to him, this is practical but also removes a bit of atmosphere. The event system I didn't like yet. They were occuring far too often, so that I would see the same event several times in short time. The ones in the start of the game were not very exciting even on the first try also. When I remember having read previews and stuff where events were described as "memorable" events which greatly impact the world, I am really disappointed, they felt just like a normal quest which can be repeated all the time and they didn't seem to have any impact on the world either. I hope they will make the events more exciting and less frequent, and with more impact on the world. Maybe it was just the beginning which was lacking also, I didn't get far yet in the world.
Graphics were ok I guess when I look at with what kind of computer and thus low settings I played it. I feared that I would be unable to play the game because especially my graphics card (HD 3870) is quite outdated, but it was ok. It didn't run smoothly everywhere, but it was playable. I will buy in the next time some new hardware anyway though, and I hope the maximum detail settings will be as great as it was when Guild Wars 1 came out in its time. I heard they said that they still improve the graphics.
Character creation was nice, you could individualise a lot of your appearance.
So all in all I feel you can see everywhere in the game that it is still in the beta phase yet and not a finished product. I have trust in the developers though that they will fix the issues until release and make it more friendly for new players which didn't (intentionally*) didn't inform themselves about all the new mechanics yet.
*I wasn't sure if I even wanted to participate in the beta before release, because I wanted to prevent spoilers and keep the experience fresh when it comes out as a finished product. In the end I tried it out mainly to see how my computer can handle it.