There is a pause, in single player at least. The pause key
Here are my impressions, and note I haven't played the earlier betas so some things may not be new/repeated/whatever

I've only had a couple hours to play so I didn't jump into any MP games, waiting for the weekend when I can guarantee the ability to at least finish a game

And, thanks to Multi's vids I pretty much skipped the tutorials.
Before I got the beta I mentioned Hegemonia in another thread, and when I actually played it, it brought back some of those good experiences. The game has a good level of depth without being overly complicated. It starts off fairly slow, and immediately you get pulled in many different directions because there's so much to do, and in the beginning resource income is slow. But, once you colonize a few planets and set up some trade outposts, it picks up the pace nicely.
The tech trees are interesting and diverse, but there's also no specialization, you can get everything as long as you have the resources for research. It would be interesting if, for example, a player could specialize in capital ship combat for some extra bonuses, or carriers, or small-ship combat. But that's just icing on the cake, as it were

The combat AI is pretty good, all in all. I've seen some good focus firing, and the auto cast abilities seem to do okay. But sometimes the auto-cast AI behaves strangely. Several times I've had my Dreadnaught bombarding a planet, only to break off to use the radiation bomb on some enemy scout entering the gravity field. Also I haven't experimented much with support autocasts (like the shield restore on one of the capitals), I wonder if it's smart enough to, say, fix up shields on one of your capitals that's getting pounded rather than a small frigate. It could be good to have basic selectable AI controls for such cases, since most abilities target either anything that's an enemy or anything that's friendly. You could have something like Ignore Frigates and Cruisers, Ignore Capitals, Ignore Structures and then your autocasts would function under those paremeters.
The enemy AI I can't comment too much on yet, since I've only done a game on Easy to learn the ropes. But even then I was cursing because he built up a bunch of broadcasting centers and I ignored them, at one point I had to scramble to scuttle some labs on one of my planets and build a broadcast center because the AI was taking it over with culture

Now after all the more technical stuff, the fun factor is definitely there. I've read that most of the effects and such are placeholders and battles will be shinier, and that's good because right now I think that's the most underwhelming part of the game. Even with big fleets battles are over very quickly because of all the focus fire that goes on. I've always imagined long engagements that left you time for reinforcements to arrive even from 2 jumps away or something, but right now there's really no time for that. I guess I can make a comparison with SW: Empire at War. There, when you were engaged in a space battle, everything was shooting everything with something, basically. Ships were flying around everywhere and large ships that couldn't turn fast would use their different turrets on different targets within all their arcs of fire, etc. Here, it's more of focus fire > pop, repeat. It's just a bit less flashy

Hopefully when the final effects are added it will feel and look like you're having huge fleet battles, as right now it's more about watching icons disappear

But still, that's a pretty minor gripe with a game that's built very well. I started playing yesterday and before I knew it I was cursing the evil evil work because I didn't want to go to sleep

So, given that the game is in beta and there are still a bunch of gameplay additions coming with beta 4, I would say Sins definitely looks like it'll shape up to be a very addictive and fun game to play! Can't wait to jump in multiplayer this weekend and get my butt kicked by more advanced players