I shoot the Magnus snuffer. I have tried many, many others and IMHO, there is no better broadhead on the market. Some guys complain that they can't get the snuffers to shoot well, but I believe it is because they don't know how or don't take the time to tune their bow/arrow/broadhead combination. If your bow will shoot snuffers in a tight group, you know your arrows are flying perfectly. That means you know that all your energy is going to penetration instead of wobble.
I used to shoot Thunderheads, but had a couple bad experiences with them. They are IMHO the best replaceable blade broadhead, but the design makes them more susceptable to deflection.
I've heard good things about Slick Tricks, however, the sharp angle of the blades makes them even more susceptable to deflection. (I hit a 400 class bull on a quartering away shot with a Thunderhead 100 grain and instead of penetrating the chest cavity, it slid on the outside of the ribs and only gave him a flesh wound so I am especially careful about doing everything I can to avoid deflections. Obviously, I have no way to know for certain that the snuffer would have killed the bull, but I think it might have.)
All I know is that since I've changed to snuffers, I've killed everything I've shot at. I'm so convinced that I've started selling them off my web page in a "pre-sharpened" version. I.e. I buy them new from Magnus and spin test them and then sharpen them for my buyers. (
http://gilaguide.com/snuffer.html)
Magnus warranties them against all defects and will replace them even if you shoot them into your basement wall. You can't beat their customer service.
If I were to go with a 4 blade, I would go with the magnus stingers.