On this page you will find links to Nike heart rate monitor reviews by users on Amazon. Probably the people most qualified to help you with your buying decision are the users of the specific heart rate monitor models in question. So take a look at the reviews they have submitted. They may either confirm your decision or make you think twice.
Nike in general produces decent heart rate monitors. The C6 and the Imara are the better ones among them.
The Pros and Cons column entries are meant to be a snapshot of the user reviews. Please read the reviews to get the full picture. Remember no heart rate monitor is perfect and they all have their pros and cons.