My group has seen some play with the Witch, the Oracle, and the Summoner. We reran the first module of RotRL (shuffling up the encounters a bit and adding some new stuff as this the second time through for the group)
The playtest classes were not the full versions and you could tell. They lack support from class based feats and have a few quirks that need to be ironed out, but all in all the ones I played seemed to be pretty cool, and hit on concepts and play styles that were pretty cool for the most part.
The Witch is a flavored alternate wizard class. It has a little more focus on the familiar and trades the wizards comprehensive spell list for a much smaller one. In exchange it gets bonus spells and abilities based on what type of familiar is chosen. It also gets a fair amount of additional abilities called hexes that can be chosen every so often as class features. Aside from some rules issues with hexes and AoO. There are a lot of touch based hexes and no real way to avoid an AoO for using them per the playtest documents RAW. IE. you cannot hex defensively so those hexes never really got used in my game. All in all this class was my favorite of the three we playtested.
The oracle is basically a divine sorcerer with a twist. They get a disability at first level, and eventually they overcome it and finally they get a special ability making them awesome at the thing they chose to suck at when thery made the character. Its a pretty cool concept. I don't remember if it had a trimmed down spell list or not (I think it does). Instead of domains oracles choose foci (whioch pretty much act as domains giving them spells and abilities). One funny thing that came up last session is that I found out the level 2 oracle of fire in our group did not have access (or the player said so at least, but knowing this player he could be wrong) to a fire spell, which was fairly amusing due to the way he roleplayed the toon. Lots of talks about the magic of fire and purging this and that. An NPC finally called him on it, and the end result was an attempted torch purge, which was hilarious for our group.
The summoner is the class that we played that IMO needs the most work. It is a class that gets access to level 9 spells disguised as a bard type class that should cap out around 6-7th level spells. It has a very restricted spell list, but pretty much all of the spells on it are VERY nice. Not a whole lot of duds to be found. They even get access to some key spells earlier than sorcerers or wizards. In addition to the spells they get a summon monster SLA (which the developer reduced to 1 round/level for the playtest even though the doc says 1 munite). The SLA is pretty good at 1 round/level, and outstanding at 1 minute per level. Finally the class gets a pet called an eidolon which is basically a point based build-yer-own monster. This ability is VERY powerful, and in the playtest doc was very open to exploitation. Luckily I looked over the forums at Paizo very hard and had a talk with my player before he made the character, so I did not end up with the tentacle monster. IMO several of the abilities in the evolution chart (the list of things you can spend points on to build your eidolon) need to have thier costs adjusted and/or have limitations on how many times you can purchase the ability. But all in all building your own monster to travel around with is VERY cool. In our case it was like the player was the eidolon and the summoner was more the eidolon's pet instead of the other way around.
So yeah, the classes need further balancing IMO. I imagine this will be in the final product as they did pretty well with the playtest for the core classes and balancing them in the final. And aside from a couple of vocal and sometimes rude folks picking apart some of the play tests (rude folks on internet forums..what is this world coming to) I think the playtest itself went really well.
love,
malkav