First thoughts on Arma 3 the Alpha.
The Pros:

• Graphics engine significantly improved as well as the performance (it runs very smooth and looks better)
• I like the new stances which allow you to slightly shift how far up you pop up over cover.
• Interior vehicle designs look very nice.

-Inventory system is a lot better
-Weapon scopes and lights can be attached now, for example I can give a squad member a scope if they dont have one for their rifle.
-Your clothing holds items as well as your combat vest.

The cons:
-The ai seems very stupid at times. I will try to keep track of this and report more specifics on the AI.
-They say they improved the sound engine but JSRS sound mod still blows everything out of the water.
-The controls are still not easy to learn, but then again Im not even sure how to handle that many things that a player needs to do.

Im not a super huge fan of the new Stratis island. Mainly is made up of hills with bushes. Very few buildings and barely any trees.

Overall very impressed though with the new improvements and this is in Alpha so I got what I expected and more! Hopefully my opinion is not taken as an insult as I very much can see the dramatic improvements. Congrats.