I had the second generation R56 Cooper (58 plate). I found it a bit underpowered (120hp), though the handling was great. It was a lot tubbier than the first-generation one I had (52 plate) and the ergonomics inside were awful (especially the automatic A/C). Mine was particularly unreliable, which has put me off Minis for life (so I went back to Golfs - much happier).
The non-hatchback Minis are uniformly awful - Coupe, Countryman, Paceman, Clubman. The Countryman is almost as hideous as the BMW X5. Whoever heard of a Mini with five doors?
The A1 is a nice car, especially in white.