You can insert the cap while using the Thunderbolt cable in case you are working in a dusty or potentially wet environment. Lacie is known for premium designs and this product is no exception. Everything just feels well designed and manufactured. The case includes a mini magnet to hold the Thunderbolt cable in place when not in use. The length of the cable is just right (enough to comfortably use it with most laptops but not too much where it get's tangled.)
Nothing creeks or cracks. Everything is solidly built and you know this will be a faithful servant for years to come.
The drive is Bus powered on both USB 3.0 and Thunderbolt which means you won't have to carry another power brick. The fact that they built it with both a USB 3.0 and Thunderbolt means they really thought about their customers (since most non Apple computers still don't have Thunderbolt ports). There is only 1 Thunderbolt port so you will have to place it at the end of your daisy chain (since you won't be able to hook up another thunderbolt product to it).
The device is designed to take a 2 meter drop and continue working as if nothing happened. We drop tested it in the office (cement floor) from a height of 2 meters and it worked perfectly. We slowly dropped it from higher up (up to 4 meters) and in our tests, it still worked great. To be clear we raised it and opened our hand, we didn't power pitch it towards the floor.
we then closed all of the ports (double checked that we closed it properly) then misted it with a salt water solution. We sprayed it until the drive was completely wet and left it overnight. We then checked it our in the morning and the drive worked as expected.
We threw the drive in a freezer bag and froze it overnight. Then we let it thaw out for 12 hours and it worked flawlessly (I don't recommend freezing your drive).
It's what's inside that counts
So the Lacie Rugged Thunderbolt comes in both a traditional mechanical hard drive configuration (1TB or 2TB) and a super-fast super-resistant SSD configuration (250GB or 500GB).
The SSD version of course is much more drop resistant than the mechanical hard drive since there are no moving parts. This is the version I tested and performance was amazing. The 500GB SSD model performed as fast as any other premium external drive I have tested. It was a joy to use.
I tested it on my Macbook Pro retina and both interfaces performed at about the same speed.