My favorite is my stainless steel set. They were
originally obtained to try to limit our aluminum consumption. They cook evenly and do a great job of keeping muffins and cupcakes from getting overly browned on the bottom. The drawbacks are that they are pretty pricy and are heavier than others. My set is split into tins of 6 muffins rather than the traditional 12. I really like this because if I want to make just 6 muffins, I do not have to fill six whole spaces with water and then try to pour all that water out without sloshing it over my muffins.
I recently purchased a 12 cup muffin tin of the traditional, dark type. I was looking for something that would be easier for my grandmother to lift in and out of the oven. It works very well, but it does brown things on the bottom a bit more than I would prefer. It was about mid-range on price and is very sturdy and easy to handle and clean.
At one point I had (and must have finally gotten rid of it because I could not locate it to photograph) an aluminum type muffin tin. The benefits of this type is that they are cheap and cook fairly well – their light color keeps things from overbrowning on the bottom. Mine, however, was truly awful – It rusted every time I washed it. If you have one that does this, wash and rinse quickly in very hot water, dry quickly with a dishtowel, and place immediately into a warm oven. This process will cut the rust down to a bare minimum.