I've had no issues at all. This is what I've tried
Ferrari 458 Italia at Silverstone International : Understeer city until you get the back end out then it turns into a drifting machine, a little underwhelming to be honest but I should reserve judgement until I've had more time with it.
Lotus Elise SC at Magione (as in the Tech Demo) - Thought it would be good to do a comparison. First off the car is a lot slower in pure laptime now, 2-3 seconds roughly. At the edge of grip it is nowhere near as understeery as before and turns in nice, oversteer is more predictable than before and to me feels more life like, crazy high speed slides are not so easy to catch however and spin out more like you would expect to in real life. Overall I think it is a definite improvement in terms of driving quality over the tech demo, it's a joy to drive.
FFB seems worse to me (in the Elise SC), not as detailed or "rubbery" feeling. I suppose you could say that it feels somewhat like a real car though I prefered the FFB feel of this car in the Tech Demo, its like the wheel feel is heavier and as a result the FFB effects are much less obvious, turning the gain down turns down the FFB effects just as much as it does the wheel weight, so it's much the same effect just lighter.
Also drove the Formula Abarth Open Wheel car around Silverstone, if you have driven NetKar Pro then this will feel very familiar to you, though I would say it is more refined in every aspect, FFB feels similar to NetKar but not quite as direct (I suppose a little more rubbery, but not Rfactor 2 rubbery). It isn't a very powerful car so it's not very exciting at Silverstone, but the car itself feels, acts and reacts exactly as you would want it to.
Thats as much as I've done, not had any issues so far and loving it overall.
One BIG BIG annoyance though. If you go out of the track bounds (and invalidate your lap) it gives you a time penalty and stops you being able to control the car properly (no throttle), this caused an accident for me at Magione. For example, I'd already made a mistake and lost time and needed to catch a slide, which would have been easy with the throttle, a certainty even. But due to the penalty cutting out my throttle I spun the car.
I hope that can be turned off or completely removed, there is no need for it.