At first, I was blown away with just how incredible everything was. The way you learn new skills, the way skills are based on weapon type, the traits, WvW (it's sheer size still makes me drool lol), the size of the world in general. Some of this stuff I already knew about, but had not experienced personally (<3 me some gamebreaker.tv !).
I started off with a necro and was having a little trouble because I misunderstood some of the basic mechanics. Like the auto-attack spell/ability. I kept mashing the button over and over thinking I had to. This, of course, becomes annoying quickly (at least in wow you're pressing more than one button most of the time). There didn't seem to be any clear path from one questing area to the next. Every class felt a little too much the same. Every class felt too squishy.
So I started to dislike my experience and began picking apart the cons of the game (to clarify --- understanding that it's a beta). Many of the things I found and analyzed I was disappointed in. I didn't like the lack of a role system (no tank, healer, etc). Crafting didn't make sense.
I was kinda discouraged because I was afraid it was going to be another WAR or Aion. After about a four hour break (courtesy of not being able to log back in lol), I took it for another spin. Suddenly, everything clicked. The skills made sense, crafting made sense and the role system made sense.
I won't say it's a staunch competitor for WoW, but I can say it's going to be a solid game and worth the money to pick up since it's F2P.