The Z?...well...
I drove it on the same day and I enjoyed the Clio a LOT more!. Coming from a 968 Sport, the Z felt similar but not better than the 968 in any way other than top end speed. Handling and steering feel is better on the 968, so I thought to myself, "why buy a Z when I didnt feel as though it was actually better than what I already had!". When I was able to give the Z some stick, it actually had a noticeable bit of initial understeer before settling into a fairly composed drift, but still, the 968 was a better handler (less understeer!).
One thing I liked about the Clio was that the power delivery felt immediate, whereas the Z had to be wound a bit before picking up, just a bit more inertia in the Z which made it feel a bit on the heavy side.
The Z is a good road car, but for my purposes (a bit of track work) the S2000 or Clio feels better suited. Id be afraid the Z would be a bit heavy on tyres and brakes with all that weight to manage, but Im not too sure about the facts on that - just a guess!
Depends on what you want really, of the 3, the Z is prob the most comfortable, the S2000 feels light and agile (pointy handling - tail felt light, which is better than understeer in my book!), but the Clio had the most feel, best noise and when the grip goes, you can sense it so well.
The Z or S2000 may win pub arguments about 0-60 blah blah blah, but they just didnt feel special in terms of involvement compared to the Clio.
Just my opinions...hope that helps!