I drive the 197 (bought one together with a friend) and two other friends are driving the 200.
My personal experience after driving my car for 8 months now and after doing several test drives with one of my mates 200 is the following :
Performance
Both cars are equal.
I've driven both models hard and they are the same as far as I can tell.
The thing I like about the 200 is the clutch, it's much softer and a bit easier to control, but that's about it if you ask me.
Looks
This is a matter of personal opinion, some people prefer the 197 and others the 200.
I prefer the 197.
The only thing I like about the 200 is the better looking diffuser.
Quality
I also prefer the 197 here.
I've inspected the interior of the 200 and I must say, it seems like Renault have saved some money here and there.
It looks very similar to the 197, but some materials have changed.
For example, the cloth used to cover the roof on the inside looks like some cheap material, in our 197 it looks better.
Both cars are very similar.
The only two things I like about the 200 is the better looking diffuser and the clutch.
In the end, I wouldn't dream of selling my 197 for the 200, but I can understand why some people prefer the 200 over the 197, it's a bit more civilized.