Well I'll certainly be buying the convertible. I love driving with the roof down and it doesn't always have to be hot enough to just wear a t-shirt. There's nothing better than having the roof down on a crisp winter morning. With the heaters set to high and the heated seats, steering wheel and neck warmers on you'll be plenty warm enough.
I don't intend to track my car or drive it to the limit on public roads so for me the convertible is a no brainer. The difference in handling due to the additional weight and reduction in rigidity due to lack of a roof probably aren't noticiable to most but the added bonus of being able to drop the top is worth every penny to me.
Convertibles sell well in the UK. Better than in most other European countries. If it's too hot then you get burnt so UK weather is great plus we're desperate for some extra vitamin D
CH.