I've not driven a 200 Cup, but I owned a 172 Cup for four years and have spent quite a lot of time driving a friend's 197, which isn't really that different to the 200 in reality. My observations:
The 172 feels a lot more raw and exciting initially, mostly because it's a bean tin with a 2.0-litre engine in it lol. The lower weight means it feels more eager and responsive. The additional weight of the MK3 makes it feel a bit less responsive, so you have to really rev it to make the most of it, while the 172 can be driven more lazily.
In terms of the chassis, they are very different cars in my view. Again, refinement plays a part, but the 197 feels much more planted and stable, while the 172 feels a bit more skittish and, on uneven roads, feels like it's "skipping" across the surface by comparison. I don't think it inspires as much confidence.
As a practical prospect, they couldn't be more different. The 172 is obviously more economical and the short gearing of the 197 makes it feel a bit "buzzy" on the motorway. However, the 197 really does trump the 172 as a road car in every other way. It's more comfortable, more refined, more spacious and just a much easier car to live with on the road in my view.
If I was to have another Clio (which I plan to), I think I would probably go for a 197/200 on balance, especially for a road car. While the 172 Cup does offer the slightly more raw driving experience (which I like), the improved refinement and easy-to-live with elements of the later car would make it the winner, especially if you're going to use it for ferrying the kids around. Even as a track car, the 197/200 would tempt me now. I adored my 172 Cup, it's my favourite of all the cars I've owned (even compared to faster/more expensive stuff), but the 197/200 is just a more rounded package I think.
A good guide for me was that, when I borrowed my friend's 197 for a fortnight, it gave me such instant confidence that I was in full heel-and-toe, drive it like you stole it mode within a few miles, while the 172 took a bit longer to really get comfortable with. I've also been thinking about replacing my Escort rally car with some kind of Clio and, if I choose to go down that route, it's far more likely to be a 197 than a 172.
Hope that helps!