The MINI Convertible suffers one major downside that is common to most open top cars – a huge blind spot. It's so bad that my lane change turn signal starts about 5 seconds before I make any kind of move. It's a signal that really means, hey I'm coming over… I can't see you, but I just wanted to let you know. In fact I'd feel more comfortable making hand signals or just yelling “anyone over there?”. Even with the top down it's still a bit of an issue.
But hey… this is a convertible. These types of little inconveniences should be expected I suppose.