So, I and seven players began playtesting the Alpha 1.1 rules as written using the Savage Tide adventure path.
For character creation I used the Alpha rules exclusively. We used a 28-point buy for ability scores and average gp for each class to purchase equipment. For hit points, I tried the Constitution score + max hp method. I allowed feats from the Player's Handbook, the Pathfinder Alpha and the Savage Tide Player's Guide.
In our first session we dealt with character generation and got through the first encounter. The party consists of two human fighters, a half-orc fighter, a human rogue, an elf rogue, an elf cleric and a half-elf wizard.
Here are my initial impressions:
Backwards Compatability: Seemed high to me. It was easy to calculate the monsters' CMB in my head, and there didn't seem to be a need to update the monsters' skills.
Combat Maneuvers: Many were tried in the first combat. One guy has a fighter who is focusing on the spiked chain; he made several trip attacks. Another player used a grapple. They were as quick to resolve as normal attacks, and we so far have not encountered a flaw in these rules.
Skills: No issue with the skills, but at 1st level that's not surprising.
Other than that, the only issues we had with the game were more related to d20 in general (we usually play C&C these days). The players seem to be pleased with their characters and the options provided.
When/if I get observations from the players, I will share them.