Hmm, let's see...
In GT6 i like:
- faster menus and loading times (it still amazes me how slow and unresponsive GT5's menu is)
- better physics
- new premium cars, also some of which are cars I didn't quite enjoy in GT5 because they were standards
- tesselation technology on some premium cars, making every curve smooth
- new tracks, and more tracks having weather and time setting
- more customization options
- 2 cars in photo travel
- the pixelated smoke which ruined countless photos in GT5 is gone
- Vision GT. I didn't really care at first but with every new car released I realise how cool of a project it really is
- the stupid XP system from GT5 is gone
- paint chips are no longer lost whan you paint a car (this was so frustrating)
- no creepy Jeff Gordon like in GT5
In GT5 i like:
- more HUD options (simplified in GT6)
- MUCH better photo locations, most of which are more detailed than the ones in GT6 (funny how PD doesn't mind using pixelated GT3-era car models and yet they take away the awesome photo locations)
- graphics in general (something about lightning and material shaders seems better to me in GT5)
- shadows. Yes, in GT5 they flicker but atleast we have sharp shadows, which to me adds a lot to the immersion, especially in cockpit view.
- better image quality (GT6 looks kind of muddy and muted)
- more options in arcade mode (mechanical damage, fuel etc...)
- the Photo Travel glitch which enables you to take photos of car interiors (I loved this, now it's removed
)
- I liked the presentation in the premium dealership, much classier than GT6
- there was something about Nurburgring in GT5. That subtle early morning, slightly foggy atmosphere made the game look incredible. Due to the change in the lightning i can't replicate that weather setting in GT6. it's a minor thing but it was one of the best GT5 moments IMO.
GT5 was very flawed and inconsistent but at its best it was amazing IMO. I won't vote yet because I believe GT6 will be expanded and improved just like GT5 was, but at this point i think i prefer GT5.
But out of everything PD released on PS3 my favourite is GT5: Prologue. Except for being low on content it was as good as previous GT games IMO. A consistent, polished release, best graphics in a PS3 GT game, it aimed for quality and it showed.