Thats a fair point. As said though, I made over $5000 worth of investment into GT5 before it was released in preperation for it. You can be sure I have given it every chance under every set of circumstances, played and tweaked to get the best out of it. It is possible that my tv just doesnt work aswell with gt5 in 3d as yours does. But that said, The depth I experience in fm4 upscaled is natural and very immersive. Although some of the menus do look funny in upscaled 3d. Occasionally a tail light might appear to me a few ft closer than the rest of the car or such. But be rest assured thats only on stills and menus. In moving gameplay upscaling seems to work very well (atleast with my samsung set) and nothing appears unnatural or out of place.
I wouldnt say my experience with GT5 3D is a bad 3D experience per say. I just felt that all of GT5's existing graphic problems (frame rate drops, tearing ect) were somewhat magnified and amplified when putting that extra load on the ps3 and forcing 3D out of it. Although the cross talk I experienced was odd as I get practically zero cross talk when watching 3D blu rays from my ps3. Next to zero when watching 3D movies from my PC or gaming in 3D from my pc either. But for some reason GT5 seemed to have alot of cross talk and that *SHOULD* be set dependant, not pheripheral or sofwate dependant. That said I tried long and hard and with many different settings, So I feel that I explored and exhausted the best experience GT5 can offer me.
Your analogy about the 2 books is quite interesting though. As most people just play a track or 2 of fm4 then compare it to the full game of GT5. Failing to explore the pages (Chapters even) including fm4's amazing community based gameplay and competative environment, store fronts, auction houses, player partys, car clubs. Essentially comparing 100% of GT5 to about 35% of forza and then saying "forza just doesnt offer an experience as engaging, immersive or addictive". I dont want to come across as being a smart ass, or agressive, I in no way intend my next comment to come across as so. But after saying "I wouldnt want to judge 2 books against each other when one may have a good chunk of pages removed" Is exactly what you have done by comparing your exhaustive GT5 experience to your limited FM4 experience. What you have essentially done is read the intro of FM4, Then put it down and said "Nah GT5 is the better book for sure"
Unfortunately 99% of people that fly the GT5 flag are in exactly the same boat. While 99% of people that have taken the time to completely explore the forza experience will say that it is the better option OR "I play FM4 and GT5 side by side and enjoy both equally". You wont find many that genuinely own FM4 and invest good time in it stating that it is as bad as most of those under the GT5 flag.