I am going to be heading for bed soon, so might as well finish off the beta with my perspective.
Necromancer was fun. Not loads of up front damage, but just annoyed multiple people with loads of aoe conditions.
Engineer was okay. Damage was lackluster, and the flamethrower was hard to use due to the flame at times shooting off to the side due to how my toon handled it (sometimes would hold it in the "neutral position, resulting in the flame plume being 90 degrees away from where it should be). The turrets were meh.
As a last ditch attempt to try and find something that I truly loved, I gave the warrior a shot. I had done the human starting area to death, so I tried the Charr.
HO-LY SHIT WAS IT AS FUN AS HELL. I spent 5-9pm blasting everyone to bits in Kyloh battlefield with my rifle, and cutting them to bits with sword/shield. It is everything I hoped the engineer had, and more. The story was interesting and fresh, and the characters were lovably retarded at times (Steelbane was the classic "giving a dumbass a high ranking position in the army" scenario.
I ended up killing him off, since the Charr are about shunning weak links, and I wasn't in the mood to fight his band of rebels that he would gather if I spared him to try and overthrow me. Good night sweet prince, may angels sing thee to thy rest. )
WvW was ultra frustrating at times, as I had the unfortunate event of the entire enemy group charging at me when I was alone, but still fun with all the siege engines. (I ended up leaving anvil rock with all the lag, instead made home at scavengers causeway.)
The only thing that bugs me is that people are expecting everything to be perfect. In a beta.
Other than that, A++ Game would beta test again.