While I originally wanted to post a more in-depth playtest report, that is not going to happen for many reasons. Instead, I wanted to just present a few experiences on classes while playing through the first two chapters of Shattered Star (don't worry, no spoilers). We used 15 point buy, built fairly traditional characters, and tried not to dumpster dive for obscure options.
The "Fighter" character was a Half-Orc Arcane Bloodrager. In building, there were few problems. Not being able to dump Charisma took a couple points from Strength, but overall led to a more "balanced" character (that is, one that doesn't need to burn a feat on Intimidating Prowess to be scary). Overall, the class played very much like a Barbarian: extremely strong when raging, still good while not, with an acceptable amount of skills. The ability to cast spells was a nice little benefit, used mostly for vanish and the odd enlarge person. We did notice the lack of cantrips acutely, as read magic was not available so we had to look up what to do without it. Also, the Arcane bloodline is amazing: the first power and spell were basically irrelevant in our game, but being able to choose between four buffs as the second power was very strong. Blur was standard, but spider climb basically made climbing irrelevant (even at low level, with few rounds) and resist energy came into play. We didn't test the other bloodlines, but looking at them, some of them may fall behind the power and versatility offered.
The "Rogue" was an Investigator. Dex-based Elf. The big impressions were that the first few levels hurt, but it became amazing after. Inspiration ended up being spent on attacks and saves because it kept the character alive, even though the 2 point cost meant they didn't get many uses out of it. Requiring training in a skill was slightly annoying, but didn't come up much (Intelligence Inspiration was not even considered, as all skills were trained by level 3 and there were so many other, strong talents to choose). Also, really hope "Extra Inspiration" is a feat in the ACG. Anyway, the dex-based nature meant damage was fairly awful for level 1-3, making the character of minimal combat relevance. Level 4 was an amazing change, the watershed of turning points. Sneak attack kicked in, 2nd level extracts (woo, bull's strength!) came into play, and the Investigator got a talent (Combat Inspiration) all at the same time. It was a slightly rough start, with low damage and few extracts and tricks to help, but post-4 was amazing. It had been a disappointing experience compared to a Rogue, as the save bonuses didn't come up, the 2 extra skill points would have allowed skills to be trained sooner, and the extra Sneak Attack would have been noticed. But after level 4 the player would not switch back to Rogue for the world. As the hybrid classes are intended to make what would have been a multiclass option into something that works from 1, this might be an issue, as taking until 4 to really come into its own is almost Prestige Class levels.
Our "Cleric" was a Hunter, which was probably a poor choice. After much grappling with the abilities, the player chose a Strength-based melee build (as ranged and casting builds benefited little from the companion or Teamwork feats, restricting those options). It felt VERY similar to having a melee Druid, but with slightly worse skills (no Nature Sense) and special abilities. Animal Aspect was nearly irrelevant, as the duration on the skills were generally too low and the stat boosts felt weak. Owing to the fact they conflicted with Belts by the second adventure, and the small number of uses was not worth ignoring one of the "big six" items, the player chose to put the boosts into Dexterity or Constitution. The effect was minor, both because it was small and because gaining bonuses to defensive stats will never "feel" the same as gaining one to an offensive stat. The overall experience was quite negative, with the player complaining about the Teamwork stuff being weaker than an Inquisitor while not getting the Wild Shape or spells of a Druid.
Finally, our "Wizard" was an Arcanist. There is very little to report here. He felt very much like a better Sage Sorcerer, with a skill list more suited to him. The ability to change spells was nice for getting rid of sleep quickly, but didn't have much relevance to the game overall. It likely would be more important at higher level, when metamagic and specific use spells become more common. The bloodline felt so tacked on I had to look it up afterwards, but that is irrelevant since that bit appears to be getting changed.
I hope this helps. I know I skipped much of the hard data, but trying to type it all out gives me grad school flashbacks, and I doubt it would really be that interesting anyway. I have it, if anyone particularly cares, but otherwise I hope the general experiences will be of some value to the playtest.