a really good feature of the weiser deadbolt is that it has a grade one rating. schlage only has a grade one rating in the primus keyway B500 series. the primus keyway is restricted. only certain franchised locksmiths can cut keys for it. a grade one rating means the deadbolt has certain superiority in things like being able to stand up to various physical attacks. go to weiser.com and read up on the weiser before you make a decision to replace it with another deadbolt. check out some independent reviews of the weiser. http://en.allexperts.com/q/Locksmithing-3110/2008/9/Handleset-Rekeying-1.htm
replacing the weiser deadbolt with another weiser deadbolt would probably cost about $50 and a rekey for it would probably run about $20.
i am not familiar with the quality of the weiser deadbolt so i cannot advise you as to how secure it may be. schlage is pretty high quality. medeco is high security but the can be expensive. i would judge a kwikset to be medium security. you can get a low end schlage for about $30.