I went from a MKIII MX5 to a SLK, in my case a 350, which I still have. Both were/are third cars, purely for fun days out.

Do try them both, but here are my thoughts.

The MX5 is a pure sports car, handles like a go cart, and the controls are a delight. I had the 1.8 which purists say is sweeter than the 2.0, and although it makes do with a 5 speed box, you can virtually drive it flat out should you wish. So why did I trade it in for a 350?

Well the MX5 is not a great car for long journeys or prolonged periods on the motorway. Mine was the softtop and frankly it's horrible with the roof up. Of course, these cars should be driven roof down whenever possible!

The SLK feels big to drive but is a good deal better in the refinement department. It also handles beautifully and grips like a limpet but the steering doesn't have the wonderful feel and fluidity of the MX5s. The SLK can be driven long distances without arriving feeling like you've done a few rounds with Anthony Joshua.

Now, the engine. FORGET THE SLK200! It's a wheezy old thing which does not suit the character of the car, even in the revised 184 BHP version.

If you go SLK, you need to go with 6 cylinders, so the 3 litre 280/300 depending on age (same engine, different name) or the 3.5 litre 350. Both are fast, the 350 is very fast! There was a V8 engined SLK55 but running costs are stupidly high

Barney100 above has the sole diesel engine the 250 with 204 BHP and that's an alternative, but to me a diesel sports convertible doesn't sit well.

Finally there's the feeling of driving a Merc, and they are special, despite what many naysayers on here will opine!

My 350 has averaged 27.9 MPG overall in my hands, a full 10 less than the MX5. Insurance is £175 per year on a 4000 miles policy. Road tax, well go for a post 2009 facelift example and it's the same as my March 06 model at £325, but avoid the years in between as they're £550. You must find a Mercedes independent specialist near you to avoid high dealer costs.

Reliability for both cars is top drawer. Both are well built, but while the MX5 interior is full of scratchy plastics, the SLKs is sumptuous.

Perhaps most telling is that I kept the MX5 for 3 years but I've had the SLK350 for over 6 years and counting. I do occasionally miss that go cart quality though!