Advantages: They are only suitable for tight spaces. They work well with angle drills or bits. I use it in my computer case (steel, not aluminum), especially in the drive bays, and it works quite well. Cons: It's not titanium. If you're used to titanium bits - they don't feel sharp so you'll need some muscle strength. Also need a metal punch and start with the smallest size to reduce walking. But as I said, they are only for special settings, not for normal beats. Other: These bits are not as good as my standard steel bits and cannot touch titanium. Could it work better with a softer metal like aluminum? They get 5 stars because they are specialty tools that work as described by the manufacturer.