There are many important things to consider when buying a snowboard such as user level, core material and user reviews. For example user level is critical, a specific snowboard (i.e Nitro Pantera) could be for advanced or expert level users so choose wisely 
, if you are not yet a pro, stick to your ski ability level. It should use consistent material from tip to tail like Powerlite Core Material for snowboards. Check many reviews on the Internet, there are many specif free review and guide sites for snowboards, skis and wake boards. More things to check would be the research technology behind the snowboard or ski technology. Selected properly, a snowboard can give you a very satisfying experience down the powderface at mach speeds with great floats. Might be useful to have a look at how snowboards are made,
[youtube=http://www.youtube.com/watch?v=7GmnLHuUo5Y]