I've had allsorts including a gen 6 GT4 and a gen 7 190 (still have it).
My view on it is that
a: the GT4 is an amazing car, very quick, and gripped the road like it was on rails. People moved over when they saw it coming (it was kitted up). But its heavy, and even heavier on fuel.
b: the gen 190 is a good fast car, but very plasticky in comparison. Needs good tyres to grip the road. Much better on fuel
As much as I loved my GT4, the fuel costs were too heavy. Plus the GT4 had to be 'driven' quite hard to get the best out of it. The 190 you can drive like a normal car, but put your foot down and its quick. I don't have the same passion for the 190, but its a good fast car - faster than my everyday gen 5 anyway.
If money was no object - ie doing low miles, I'd say get a GT4, otherwise get a 190