I work at a school that has over 500 laptops, split between Lenovo Thinkpad's and white Macbook's.
The laptops are housed in cabinets with the chargers secured in. You disconnect the charger, pull out the laptop and use it.
Our Lenovo chargers? Well let's just say I am waiting on an order of 40 to replace the frayed and damaged ones. And 40 won't be enough.
How many Magsafe chargers have we replaced? I think 1 maybe a couple years ago.
Seems like they are well designed to me.