I think it was two cars (viper and evo if memory serves, though I am prone to waking dreamstates), one or two race events and a small chunk of the open world map. It was definitely just a small taste, but enough to get a handle on the driving model and open world elements.
This PS+ seems like a lot of content for a demo. But its hard to exactly peg just what the hell this is without knowing the full game and cost of upgrading it ;p
k, back from checking.
It's three cars. The Dodge Viper, Lancer Evo, and Ford Mustang. Free Roam can be done with the first two, but once you switch from the Viper to the Evo via entering its event, there's no way to switch back (there's no garage in the demo).
The demo contains:
3 cars
4 unique tracks
Standard point-to-point race
Showcase race (versus plane)
Street race with traffic
Speed traps
Speed zones
It accounts for most modes available in the full game, minus circuit races and challenging festival racers as far as I can recall. It also maintains community features, so each tracks has online player ghosts to race against, and you speed trap and speed zone results are compared with other players on the server.
The main differences I see between the Horizon demo and Driveclub is the lack of direct multiplayer, and a lack of progression. There are no bars to fill, and no objectives to complete once you're done playing each of the featured races. All there's really left to do at that point is free roam, or return to the events for another go (and compete against rivals). It makes a significant differences in terms of how long a player would be likely to play the game for, but I don't think Driveclub PS+ is actually significantly ahead in terms of raw content.
Forza horizon is an open world racer. Which in the demo you can only freeroam with one car. Its nowhere near comparable.
Even still, that is one game. The general way this goes is racing demos have very little content.
Comparing other genres is just silly. Especially arena shooters.
Well, I did make a Test Drive Unlimited comparison too, but nobody has acknowledged that one yet. I don't see how Horizon being open world actually makes much difference though. When you're competing in race events those tracks are just as unique and designed as any other racer. It's actually one of Horizon's main strengths over similar games like TDU, the tracks don't feel like randomly generated points.
And I'm not stating that demos with as expansive content are common. I'm saying that I don't believe DriveClub's content really places it outside the realm of a demo. There have been demos offering similar content in the past. What appears to set DriveClub apart from similar demos would be an extended sense of progression, so you wouldn't complete each of its races once and then stop playing.