So far I tried, in order:
Qunari mage: Pretty awesome, and it's easy to oversee the battle, in case you need to give some commands in tactical view. Widest range of choices too, imo. 3 different elements each with their own effects, and a support tree as well. However the save got bugged, and now I can't play it any more. Just before I got to pick a specialization too. Got to level 10~11 or so. I mostly fought with a tank warrior, a 2h warrior and a second mage in my party.
Dalish archer:
Boring, imo. I don't like the archer class at all. The attacking animation is always the same draw and weird 'ptoing' sound, which got annoying to me. Skills, well... most felt exactly the same as the standard attack, but with a longer draw animation. I deleted the char at level 6 or so. Though this might just be me.
Two-handed warrior:
I tried the warrior in my party. Actually pretty fun, and more challenging since you're up close and personal. Not my style though.
Sword and shield warrior:
Tried in party again. Looks like fun, but I'm not that good with the shield block mechanics yet.
Dalish rogue:
I'm having a lot of fun with this, and it's becoming more fun the more I level up. So far I only have Stealth, Twin Fangs, and Flank attack as active skills, but dashing over the field with Flank attack, sneaking up on enemies and ripping them apart with Twin Fangs and some normal attacks, and moving on to the next is a lot of fun. Not as challenging as 2h warrior imo, since you have stealth and can lose aggro instantly, or use flank attack to dash out of harms way. Currently level...10 or 11, and working on the Assassin specialization quest.
I plan to remake a mage if I can't get my save file to work any more, and I still want to try a tank some time in the future.