This game is outstanding. To be honest, I think sequel burnout is preventing some from appreciating it as much as one could with a fresher perspective. I understand; I am glad I didn't already play FH4 first.
Forza Horizon is reborn, IMO; this game gives me more of the vibe of FH1 than the middle titles, like it's not quite so much a slave to popular appeal (or routine, perhaps more accurately). It's not without its faults, which includes some carryovers from past games, but the crazy bastards actually went and did it -- they actually meddled with their award-winning accessible formula!
First, the handling is much improved. While I'm playing the game with the benefit of my G25 now (great fun), I began the game with a controller for a more accurate comparison to previous games, and spent some more time with a controller again. It's not an exaggeration to say there's little to no familiarity in my experience! It would only take a brief play to note the same old safety-net characteristics that turned me off from the Forza brand (as in FH4), and very gratefully, those characteristics have been scrapped or smoothed over. There is a much greater sense of weight distribution and weight transfer, oversteer control is more accurate and rewarding, and there's a lot more entertainment value across the lower end of the performance index.
Second, I'm sure it's not just my imagination that the roads are narrower on average than FH4's caricature of GB's notably tight two-lanes. This quickly stuck out to me in a video review I watched. Playing the game, more care was put into the road/map design this time around, so despite the same old limited penalty for leaving the pavement, there is more motivation to nail apexes. I have covered most of the roads (more than 500), and overall I'm pretty pleased with the map. I still think it could have been somewhat larger for the cost of some detail, but this time around that's more akin to asking for a second serving.
In all, I'm happy to say that PG and T10 did a commendable job of addressing my main criticisms of the franchise. FH5 is a breath of air for me with this hobby, which is wonderful.
BTW, to report on how my PC version is going: I have been experiencing the constant network problems, which interfere with Horizon Life, but no other significant hurdles. My laptop runs the game smoothly and beautifully; the environmental art direction really is impeccable in a way that compressed video cannot do justice.