I love cutting hair with a straight edge razor. When used right, a razor can give you a textured cut or a classic one-length bob. Razors don't necessarily need to be used to "thin out" hair - they should always be used very deliberately and should never damage someone’s hair. Despite what people think, you can use a razor on straight hair, curly hair, super curly hair, fine hair, medium hair, and especially on thick hair. It just has to be done right.
The key to a good razor cut is a hairstylist’s training. Each part of that tiny (and sharp!) blade is meant to be used in a specific way and when not used correctly, it can cause a bit of a disaster. If you're a hairstylist, please learn how to properly use a razor before picking one up. If you're a client, make sure to choose a stylist that's been well-trained before getting a razor cut.