So far I've only tried the classic content (as that is what I am most interested in racing). I expected to like the 911 Carrera RSR 2.8 the most, but at the moment it is my least favourite. It starts well (as expected for a rear engine car), but I can't get any speed out of it (wheel user). It doesn't seem competitive with the Ferrari Daytona - at least not in my hands, but it may be fine with a better driver. A lot more testing will be required because I am hoping to host a series for those two cars.
The Porsche 908 raced at the Targa Florio so I picked the nearest track in character in the game - Bannochbrae. This car is absolutely brilliant at this track - fantastic - thoroughly recommended! SMS have put this car in Prototype B, which is fine for now, but hopefully they add some more 3 litre prototypes and separate them out as it feels very strange sharing a track with a Lotus 40 - a bit of an immersion killer and the small number of liveries makes the car a poor pick for one make racing - surely Porsche could have been persuaded to allow some fictional liveries?
I would really like Classic Sebring so I could pretend to be Steve McQueen when he raced the 908 which he did complete with a dodgy foot - he was so keen that an injury which would have stopped anyone else didn't stop Steve!
I picked Brands Hatch for the 917K, but I chickened out of making it wet and trying for a Rodriguez moment. Really enjoyable car - fantastic and brilliant liveries. I will get a lot of use out of this car. SMS have put it in a class on its own - Prototype A, hopefully this means that other cars are coming to the class such as a Ferrari 512M and / S. IF this class is properly filled I think it will become my favourite in the game.
I tried the 917/10 Can Am car before the 917K which perhaps made that easier to drive! First try was at Laguna Seca - very challenging - the speed and acceleration are so good that I will need to relearn the circuit (and all circuits!) just for this car, however it is great fun with a good sound so well worthwhile. Next I tried Watkins Glen which really suited the car well and finished off with Silverstone Classic - you can really open the car up on this track and exploit the fantastic power and grip.
The 935/78-81 - I am sure there is something wrong with this car! Another poster said that the turbo wasn't working - it certainly feels that way and I found it impossible to keep up with the other AI cars in Group 5 - as if it has no power - hopefully SMS can fix this quickly.
I tried the Leipzig test track and really liked the bus stop style chicane in the middle of the big corner - I think this track will be well suited to the Formula Rookie and Lotus 25 and possibly to the slower saloon cars, so I will try those on it next and as another poster suggested maybe Ford Falcon V8 Supercar.
I feel like the 908, 917K and 917/10 will easily provide me with good value from this pack and I hope the next two packs contain some equally enjoyable cars.