We had our first game and it was... interesting. We played the introductory Dead Suns Part 1 adventure path by Paizo with a party of 5 players and a decent mix of races/classes/abilities (two soldiers, one operative, one envoy, and one mystic). About the only core role/class we were missing was a technomancer i.e. space wizard equivalent. The setting and rules are so so and what you'd expect from Golarion in space overall but the balance in the adventure path was off (even factoring out mistakes made by the GM that artificially inflated the difficulty).
First off I'll comment about the general overarching game mechanics. They're pretty much what you'd expect from a D&D3X style system and it's easy to catch on to the basics if you're familiar with the older variants. That said... there are many significant changes like being able to multiattack with penalties as a full round action without having to first unlock the second attack at high levels. There are also minor changes like diagonal movement costs and magic missile not scaling with level. For vets of multiple prior related editions, remembering whether the second diagonal costs normal or double movment (which seems to flip flop between various editions). All in all, it's familiar and comfortable but certainly not revolutionary or groundbreaking in any way. It's D&D3X in space for better or worse.
The art in the books though is full color and top notch assuming you like the style (which I do). The races introduced feel different and are most certainly not just the old fantasy tropes with a "space" adjective added in front of them. If you do want to play those legacy fantasy races, the core rulebook does include them later on in the rules but I'm glad that they're not the focus. Each class is unique and varies enough from the old fantasy equivalents to feel like they're their own thing.
Unfortunately, I find the setting to be a bit of a let down despite the above. It's basically an advancement of the old Pathfind Golarian setting which admittedly I was never a fan of it but neither was I critical of it. There are new races and planets like I mentioned but the core setting and default start is basically just a big space station right above Golarion (or more correctly where it should be as it disappeared) and there are other planets that are just fantasy tropes in space (like the planet of space undead ruled by space lich overlords). Maybe it's just me but I kept finding myself thinking "oh, that's just the space *fill in the blank* equivalent". That's due in large part because of the actual Golarian/Pathfinder parts ported directly over as well as those just heavily influenced by the fantasy setting. I would personally have preferred a completely independent setting but I recognize the obvious potential business benefit of leveraging a previous industry sales leading game (Pathfinder) for easy conversion into your new project. While that gives the game relatively easy access to a large playerbase right out of the gate, I can't but help feel that the setting and game will suffer for it in the long run. YMMV.
Finally we come to the Dead Suns adventure path. In short, as an old 3.X GM and player for years, I found the balance in the adventure path to be suprisingly off but a large part of that was because of two big mistakes by the GM that inflated the difficulty unncessarily. The first encounter after the players introduce themselves to each over is CR4 (and that's assuming you think that rating is accurate..see below). Your first interaction before any real roleplaying with NPCs is to get your feet wet with an "Epic" difficulty level encounter for 1st level characters and presumably new players to the game. The GM was supposed to only attack us 1/6 of the time but he must have missed that part in the setup (and combined based on common sense two encounters into one the next time).
Regardless of his mistakes, the CR 1/2 (as in one half) street level gang thugs we were facing had the equivalent stat wise of dex 18 weapon spec and focus shooting. No big deal, right? Just use some social skills to beat the encounter nonviolently, right? Yeah, they also had the equivalent of Cha 20 and full class skill rank in intimidate to boot. Their actual stats were nothing close to that but their end bonuses for both attacks, damage, and some skills were significantly higher what was possible for us as 1st level player characters. They were markedly better than CR1 opponents should have been let alone the CR1/2 individually they were listed as.
The GM commented that his main group had a very hard time with the scenarios as well. I asked another Starfinder GM and he said that Paizo does that with most of the official encounters and that he personally actively encourages his player to NOT fight but find away around combat. That wasn't an option for us in the first encounter as it was literally scripted that the shooting started right as we arrived and we were caught in the crossfire. That trend continued throughout the game and the Deus Ex NPChinima had to save us yet again later that night in the next big encounter.
I'm willing to give the game another try (and will actually be Gm'ing next time as we convinced the GM to join us for a single game only). Although we didn't reach 2nd level yet, I forwarded the group a "loan" of 300 xp to reach 2nd level to see if the equity between characters and published encounters is more balanced later on. I suspect I'll still have to adjust on the fly some of the crazy bonuses down a bit though but we'll see. All in all, at best the experience overall was mediocre although I will admit that it was nice to sit down at a table with fellow gamers and do anything for the first time in years. I'd give the game overall 2 1/2 stars so far but the Dead Suns campaign only 2 stars due to the perceived lack of balance for a supposedly introductory 1st level adventure.