@Ironman
You're right, GT5P was just a showing of what GT5 could be when it's released, it's pretty much what PD did with GT4P as well. Obviously GT5 and Forza will be better than GT5P, they'll both be a full game, worked to exhaustion by crews dedicated in bringing the best game that they both can. You can't measure better, because each person will give you a different answer, I personally think GT is better than Forza, after having tried both, because it gives you a better feeling of the driving per se, but Forza does a great job as well in giving you that same feeling as well, especially if you play it will all the driving assists off, the experience is really good.
For the Trailer of GT5 being CGI or not, PD has the history of being a really leak-free developer, they'll just show you what they want you to see, so I really don't care about the trailers, because I know that they'll deliver, just as they have in the past, so i'll be happy when I finally play the game ;). The same can be said for Forza, if by the time of it's release, my financial capacities allow me to buy the game, I'll definetily do so, because as a racing and a game fan, I just want to be able to play a good game ;).
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"