IMO beta 2 is a 100% improvement over beta 1 (it should be because beta 1 was a system compatibility beta). Ive only played beta 2 for a few hrs on easy so far, and this time easy is much more of a challenge than hard was in beta 1. Im playing a 40 planet single star 3 AI FFA, flags, bounty's, and Pirates! (Yarr!) I haven't got to building major cap ships yet, and ill go into that later.
A few good things i noticed right from the get go.
You can toggle on/off the skybox environment in the options now

If you dont like the ultra bright nebula's just toggle them off for a classic black with stars background!
The phase lanes IMO have improved slightly. I am still in favor of fully connected maps, but the new system generator is much better than beta 1 from the few maps ive seen generated.
The AI is much more aggressive this time around. Especially the Pirate AI. For the 1st time my capitol was attacked by an enemy fleet in the very early game, and i damn near lost it! (4 corsairs, 3 pillagers, and a group of rogues) I had to rush my flagship fleet back home to fight them.
The new system of population/tactical/logistics/squad cap upgrades makes things a little interesting. I was used to the upkeep system from beta 1 with no hard unit, or structure caps. This system forces you to think about what structures you want to build on each planet because real estate is finite now with 4 max logistics slots at a terran world you have to chose if you want that world to be a trade world or a production world, because you cant have both anymore. The good point is no more broadcast center spammage.
3 hours into the game i described above, and the only capitol ship i have managed to build was an Akain cruiser. I am having a major Crystal crisis even tho i colonized an ice world, and am in tier 4 of crystal harvesting with a refinery built. The majority of my crystal has been going into research. I have been using the black market quite a bit more to acquire crystal since metal comes in excess now. I do have a nice defense fleet built, but it only has 2 cap ships. The lack of cap ships makes rely heavily on planetary defenses now especially with the aggressive corsair flying wandering pirates ("booty off the port bow!" that line cracked me up). It is much harder to set up your economy, and maintain it now. Nicely done.
The bad things i saw. 1 graphical error in the tutorial where a highlight was in space, and not around the action bar where it should have been.
New frigs are nicely done. I havnt built any of the new cruisers yet. Speaking of which there is research for the cruiser/carrier which i researched, but there no icon to build it anywhere in ether the frig, or cap ship factory. Where do you build it. or is it build able?
While psycho wandering pirates is a good thing, it can also be bad especially in the very early game (1st 5-10 minutes). Like i said earlier the pir8's almost wiped me out at my home planet before i had any means of defending other than my flagship, and 4 cobalts. If it was a no flagship game i would have been dead. There should be a time delay before they start rampaging.