The Animation
I thought the animation and pony designs were great. 
But I really thought the pony mecha Sprout built could have been more interesting. A giant steampunk pony robot, how cool could that have been?
One thing bugged me. That was that cutie marks were only on their right flank. Hopefully they fix that for the series

Voice Acting
The voice acting was really good too.
I wonder if these celebrity voice actors will stick around for the show though.
I hope Alphabittle, voiced by Phil LaMarr, will be on the show some of the time. Some Samurai Jack references would be cool. "Got to get back. Back to the...tea shop."

Songs

My favorite song was "Angry Mob". So many good jokes in there. It could be the theme song of the human species.
I also really liked "Gonna Be My Day".

Random Stuff
In the map in Sunny's house we see that the Everfree Forest still exists.
Everything here is written in English rather than ponish. I remember on one of the commentaries they were saying they didn't use a real language so FIM would do better in other countries. I wonder why they changed that here.
For the first time we see how physically dangerous a unicorn horn can be. Izzy took down a huge tree in seconds! The only example I remember in FIM was that stallion popping balloons.
I liked all the winged animals. I'm sure it hasn't been long enough for new animals to evolve so they must have been made magically. 
"Just try not to start a war while I'm gone." You had one job, Sprout!
The Canterlogic logo reminds me of the Momcorp logo:

I was interested in the technology all the ponies had.
Pegesi seemed to be at the same level we are now.
Earth ponies were maybe in the eighties. We saw bulky old tvs and no personal electronics but a pretty big industrial factory and street cars.
Unicorns seemed to be basically at the same weird in between level ponies were at in FIM. The main technology we saw was that wooden dancing game powered by running aardvark-mice since there was no magic to power it.

Theories

Okay let's get the depressing part out of the way. I'm pretty sure everypony we knew(with the possible exception of Discord) is dead. Yes even the princesses. 

Magic seems to have changed and evolved a lot. I doubt ponies control the sun and moon and weather anymore unless there's some secret cabal that could still use magic. In a lot of stories magic declines as technology increases. And of course the pony races being separated made most of the magic go away. But there was at least one piece of magic left. They all still had cutie marks. And there were at least two more hints of magic: Hitch with the animals and Izzy seeing the "sparkles".

I think Twilight had a lot to do with this story. Her cutie mark was on Argyle's notebook and I'm sure she created these crystals because she foresaw a time when ponies would break up. She probably created the lighthouse too to help disperse the magic. It probably took all three races working together like the hearthswarming magic. The first time they put together the crystals there was no pegasus there. Then they activated when the three older ponies helped put Sunny's picture together.

I wonder if other species will be involved in the show. Probably depends on how long it goes on. I'd guess ponies are again scared of them even more than of each other but another story arc about them becoming friends with other species would be pretty repetitive.

Relations
There seems to be indications that some of these ponies are related to the ponies we know.
The most obvious one is Hitch having animals following him around like Fluttershy. With magic now maybe he'll be able to communicate with them. Fluttershy having kids with Discord is a whole thing to think about but anyway.
Izzy obviously seems a lot like Pinkie but there's also that thing where she talks about seeing ponies' "sparkle". Sounds something like Pinkie Sense to me.
Sunny lived in the lighthouse, her dad had a book with Twilight's cutie mark, the earth pony crystal was in their home the whole time, and she was the one who brought them all together.
The pegasis royals seem to have something of Rarity in them. That one's pretty tenuous, I guess.