If you do not mind their tendency to be as engaging as telemarketers, Opels are decent propositions.

They often possess Teutonic toughness, fine ergonomics and, of late, styling that is easy on the eye.

All that adds up to a fair compensation for not being the life of the party. But hold on, what about the car pictured above - the new Astra TwinTop? Surely it cannot be deemed dull? It's a convertible, for goodness' sake.

And you know what? It isn't dull. Not entirely, anyway.

Drive the TwinTop (what a catchy name) with the roof up and you could well be driving a refrigerator. As efficient a commute as it is, it leaves you cold.

And sometimes, it rattles like it is filled with beer bottles.

That and the drone of its 1.8-litre Ecotec engine are all that keeps you awake at the wheel.

The engine has been tweaked for more power than when we last saw it in the Astra GTC two years ago, but it's still unexciting.

But fold the roof away by depressing a button for a quarter of a minute or less and the Opel transforms from zombie to Zouk.

The top is a three-piece job like the one on the BMW 3-series convertible and Volvo C70. You never tire of watching the mechanical choreography.

The Opel's canopy is done by Canada's CarTopSystems, which has supplied folding roofs to other illustrious models like the Mercedes SL. The roof has five electric motors, eight hydraulic cylinders, 13 sensors and 14 joints.

When it is folding (or unfolding), you can see and hear many of these bits.

The TwinTop is smaller than the 3-series convertible. But with its roof up, it offers more luggage space than the BMW. With roof tucked away, it has about the same stowage capability.

Driven alfresco, the Opel is almost delightful. For one, you don't hear the cabin rattle anymore. You get that sense of freedom every open-top car offers.

And you get an extremely powerful air-con that keeps you cool and dry even when you're basking in the midday sun. Makes you feel like you're in Europe in spring.

The car handles clinically, and its ride is neither plush nor punishing. The body betrays a bit of scuttle shake, especially over manhole covers and the like.

Otherwise, you're left to enjoy the journey - completely undistracted by the drive.

What's more, the TwinTop feels safe. And it accommodates four adults with minimal fuss. While ingress and egress pose no challenge, its huge and hefty doors are a pain. Their hinges need improving. Opel can look to other big doors for ideas.

Like those on a refrigerator, perhaps?

Price: $113,888 with COE
Engine: 1,796cc 16-valve inline-4
Transmission: Four-speed automatic
Power: 140bhp at 6,300rpm
Torque: 175Nm at 3,800rpm
0-100kmh: 12.7 seconds
Top speed: 189kmh
Fuel consumption: 10.8 litres/100km (city)
Agent: Auto Eurokars