I've always used the Clarins instant tanning gel. I liked it because you start to see the results quickly (within an hour) and it dries quickly, so you don't have to wait forever to get dressed.
No matter which you choose, there are some things to keep in mind.
First, you want get completely undressed before you apply it because it will stain your clothes -- including your underwear. Also, don't get dressed until it dries completely.
Next, make sure that you wash your hands thoroughly after you apply it -- make sure you scrub around your fingernails. If you don't, you will get dark tan palms and nail beds -- not pretty. The Clarins works so quickly, I usually wash up after each leg.
Finally, make sure you go slowly and avoid putting on too much at first. Apply it, wait a day to see how you like the color, and then add more gradually. It's easy to add more than it us to wait out a bad color.
The tanner basically dyes your skin, so it will last as long as the upper layer of your skin does (usually 3-4 days) before it fades. It will fade more quickly in places where you shave.
Lastly, sorry, but the things that make the tanners work also make them stinky. Some smell less than others, but you're not going to find one without any odor.
Good luck!