For me, I was pleasantly surprised.
To be honest, when I heard of the limited car/track roster and the lack of the classic GT Mode, part shopping etc etc, I was on the verge of just sitting this one out. I was actually quite bummed out because I, like so many others, have been waiting a
long time to get my hands on a new Gran Turismo. Especially since I sold my PS3 a while ago and could therefore not get my GT fix with GT6 anymore.
After the open beta started I started visiting this forum more frequently again, lurking and checking the feedback, and it surprised me how much of a positive feedback it was getting from the community here. I missed out on the beta as I was travelling, but I figured what the heck, I'll just splurge for the Pre-Order.
I'm very glad I did as I'm having a blast! I'm really liking the driving model, and I'm happy it's very much playable on the pad. I used to race with a wheel in GT5 and GT6, but I don't have one at the moment and not sure when I can get one.
I have always been a offline player, never really been much of a fan of online gaming so I surprised even myself of how much I'm enjoying Sport Mode. Granted, I haven't race nearly as much as many others here, only have 11 races under my belt so far, but with a lone exception of one race, all of them have been heaps of fun.
I'm also surprised how much I have played the Campaign Mode. Chasing the gold is fun and satisfying. And don't get me started on the Photo Mode/Scapes. So much time has been spent there already, and I'm starting to slowly get the hang of the Livery Editor and really enjoy messing around in there. It does have it's downsides, biggest IMO being the lack of layer grouping, but it's not a deal breaker for me. Especially with the custom decal uploader just around the corner, we'll see even more variety of liveries on the track!
The custom race feature is also pretty in depth and a good way to jump into a race to your liking, although I'd like to see qualifying in there as well.
It's not all positive, of course, as the lack of proper classic GT mode and the lack of variety of cars is definitely the game's biggest flaw, but it doesn't ruin the experience, at least not for me.
So all in all, I'm really glad I got it and I haven't even touched another game since release
But as always, this is very subjective and I know not all agree, so to each his own.
If you don't like the game, great. If you love the game, great. If you think it's just OK, great. Each and everyone is entitled to his or her own opinion on the game and it is just as valid as the next. As long as you don't try to force your opinions on others, and rant on those who don't agree.
Happy racing!