I recently got new binders, and realized that, even having bound for two years now, I still make some newbie mistakes.
Now, I don't know about Les Love Boat binders, or about the Kingdom whatevers, but I do have some good knowledge about Underworks. I've had six binders from them over the past two years (you need to have several of them, if you can, like bras- as horrible as that sounds, in the case you can't wash them every day or every two days) and I can't say that I've ever been displeased.
The sizing sometimes tends to be an issue, however, if you're on the cusp. I've been on the cusp of a xl to l for the entire time that I've been wearing a binder, and it gets pretty annoying. Now, just like with improper binding with ace wrap, or other materials that aren't made for binding your chest, an Underworks binder can cause serious damage if used incorrectly. When wearing a binder that is too small it can cut into your sides, right under your arm pits, as well as cutting into your shoulders due to prolonged constriction. If you have a full length binder, it can cut into your waist if it is too tight - just one last thing to thing about. I'm sure there are some ways for someone that is on the cusp to get away with this, like possibly padding under the straps, or wearing a shirt underneath your binder - though that might cause you to be a little sweatier.
Which brings me to part of another topic. Binder cleanliness.
Depending on what you do for a living, your binder can pick up a lot of unattractive smells. Smoke, perfume, food, grease any smell that you can think of. Just like an over shirt that you would change or a pair of pants, binders need to be considered under that same idea of hygiene. They get nasty and dirty and can cause rashes and other things when they aren't cleaned properly. Not to mention, an uncleaned binder can also smell. It's best for you health to have more than one, and even if you can't get access to a washing machine, you can hand wash a binder and let it air dry - they don't take that long and the amount of good you'll be doing for your body will be great in the long run.
I'm pretty sure there are a lot of other things that can be said about binder safety, and I'm sure I'm not the only blog that has or will make a post about it. Binding properly is a big thing, and if you improperly wear a binder, if can be as bad as binding with ace wrap. Get educated, don't get yourself hurt.