I've heard differing opinions about the durability of skinny masts and I'm trying to decide whether to buy one.
Many wave sailors swear by the Powerex but some people reckon that the main reason the Powerex skinny doesn't break is that they're new. Newer mast, less likely to break. Like all products, a lot depends on the quality of the manufacturing.
And skinny masts create less wind resistance and less disturbance to the air flow across the sail. And are often lighter. However, you also have to cough for a new extension

I haven't used a skinny mast except on borrowed gear so I don't really know which way is the best. Has anyone tested breaking strains on different masts to see which is the strongest?