I prefer GT5 over FM for many simple reasons:
* GT5 has a "Soul" due to their awesome support (PD / Sony) for multiple racing wheels. I was hoping FM4 would branch out more than just Fanatec and Mad Catz but once again they have failed to attract more quality wheels. Instead, they choose to water down the series with Kinect and that crazy looking speed wheel
So too me, I feel like PD / Kaz value racing wheels and giving us the best experience. A nice DFGT wheel can be had for much less than those new FFB wheels coming out for FM4. 👍
Granted, FM3 gets props. Any kind of car I could want I can drive with a cockpit. 👍
I just dont like how Turn 10 is going after the lowest common dominator. But hey- I already have a Kinect for the family. So what the heck, we will probably like it. I might still order a Fanatec later.
* So the main reason is my T500rs doesnt work on xbox 360. Dont really want to unload all that money on a Fanatec. So i might wait to get FM4 used like I have always done for Forza series. Nothing personal Turn 10. Great games. But yeah, the racing wheel options are still really lackluster unless Fanatec can step up their game and actually keep wheels in stock for people. I still might get FM4 new though if they release more info and trailers that have real substance (want to see car list, how does it look in full 1080p cause FM3 looked bad on my 55 inch plasma all jaggied and stuff )
* I also feel that FM4, since its coming out later than GT5, should be able to step it up to at least 24 players online racing. Just coming out with 16 players is sort of just trying to "keep up" with GT5. 16 players still falls wonderfully short of PC sims.... Really, do most real life races only have 16 cars???? The races I watch seem to have much more along with pits, tire wear, etc. Let's step this up. In iRacing we have much more than that for example along with rFactor. No one is stepping it up here.
* No mention of detailed pits at least on GT5's level. I am really, really addicted to pits (I've been playing lots of PC sims lately). If they once again lack pits then I will consider GT5 more realistic in this aspect
* So for me, GT5 has a "Soul" due to at least trying to be realistic (pits+) while I think Forza is evolving in a different direction. It has a 'soul' of its own but it's one that caters to the masses. Controllers will work super awesome out of the box. They play with gamepads in their demoes. They talk about focusing on "cars" and not so much on racing. Kaz injects a Soul into gt5 series with his passion for racing (like real life racing, etc) while dan (from Turn 10) feels like a Marketing exec too me. But you dedicated forza fans would know more about Dan so I would defer to other posters on that
* Lack of 3D. I am looking forward to going totally 3D racing in the near future. GT5 supports 3D
[edit, added more points]