Not to be overtly negative here but I gotta be honest, after buying my brother's Xbox One off him in September for the low, low price of $175 and picking up FM6 on launch day, I've already sold them both. Forza 6 is a fine game, but it didn't really impress me. I played all of the 360 Forza titles, and though I never fell in love with the series for more than a few reasons, it was a model of consistency and I had a lot of great times with each of those games, especially online. With FM6 however, I was expecting a major generational leap, and I was unsatisfied. FM6 felt a whole lot like FM4 (and FM3 before it) to me in just about every way, from the physics, graphics and lighting, and career progression to even the customization options and UI. I could spot the same flaws in certain car models that I did in FM4, and the selection of wheel and cosmetic options was just as hopelessly dated and slim. Every year or two I pick up a new Forza release — be it Motorsport or Horizon — and every year I get the sense that not much is different beneath the surface; the groundwork, engine, and assets were laid out many years ago, haven't changed and possibly never will because of the clockwork 2-year development cycle Microsoft imposes on these two otherwise fantastic studios. In that way, Forza is kind of like the Madden or MLB The Show of racing games — still technically good, but never surprising.
I suppose what I'm saying is, for better or for worse, Forza needs to feel fresh again to be relevant and sell. I didn't like GT5 at all, but at the very least I could tell from the first time I played it that it was nothing like GT4, and that intrigued me enough to stick with it for much longer than the game deserved.