Essentially, there are two types - step-in and strap.
Step-ins
Step-ins are great for a lot of people. Once you get used to them they are quick to get in and out of and many of them can offer a faster "toe to heel" response while turning than conventional bindings. The drawbacks are that some of the mechanisms are tricky to figure out and most still have problems clogging up in deep, wet snow. Something we get a lot of here in Whistler.
If you're really sold on step-ins, make sure you spend time getting the right boot. Comfort, again is your first priority and you'll find that step-in systems with the highback on the binding and not in the boot will be more comfortable, both on the hill and walking around the lodge. Just ask for an "External Highback" and you'll see what I mean. When trying them in the shop make sure you're comfortable with the whole "stepping in" process (it will eventually become second nature) and that while in the binding you feel solid and secure. Also, while you're standing there with the board on your feet, see if you can lift your heel in the boot. If you can, this is called 'heel lift' and you should try another boot if tightening the heel strap or lacing them up tighter doesn't fix the problem.
Conventional or "Strap" bindings
When the big step-in boom kicked in a few years ago, conventional bindings were forced to improve in order to keep up. And improve, they did. Here are a few things to look for.
Metal Baseplates Metal baseplates are going to be stronger and stiffer than your average plastic base plate. This is neither good nor bad. Some people like the stiffness and response of a metal baseplate; others prefer a little "give". If you're on a budget, metal may give you a longer lasting product than a similarly priced plastic binding.
Plastic Baseplates A high-end plastic baseplate will not break on you. They will exhibit a little more flex than metal, but most people don't find this a negative and in fact find that "give", more comfortable. My only advice would be to steer away from plastic baseplates the lower in price you go, as the quality of plastic tends to drop with the price tag. Women and kids, of course don't have to worry about this as much as big dudes. It's pretty rare that lighter person breaks a binding these days.
Set-up
Even more important than what binding; is how they are set up. It's amazing how uncomfortable a strap can be when it's not adjusted for your boot properly. The same goes for the highback lean and rotation. Each of these parts are designed and shaped to fit the boot in a very specific location - that's why they are adjustable. Don't just hand the shop staff your Visa; take advantage of their experience and get them to set up your bindings until they feel secure and comfortable.
