The z-wave alliance requires locks and security devices to use the optional z-wave security protocols - the early Kwikset did not do that and shouldn’t have been certified. The z-wave vulnerability in Kwikset locks is not present in anything marketed today. They resolved the issue and stopped selling the vulnerable version. I still wouldn’t buy it.
Kwikset is the value brand.
Schlage makes a z-wave lock that has ANSI Grade 1 (not all of them do though so check before purchasing). The ANSI Grade measures the resistance to force and the longevity of the mechanism. The Yale Real Living lock is a grade 2. Go with the grade 1 - there isn’t any reason not to (the price is the same or less for the Schlage). If you have a grade 1 deadbolt, you should consider reinforcing the door jamb with something like Armor Concepts’ Door Jamb Armor. Don’t bother with an expensive deadbolt if there is only a matchstick holding the bolt in the jamb.
ANSI doesn’t measure the resistance to surreptitious entry (picking or bumping). The bypass cores in all of the locks can easily be picked in a time that is similar to the smart key vulnerability. If you worry about lockpicking (it very rarely happens in burglary) then replace the core with a high security core with a restricted key profile. Medeco, Abloy or Schlage Primus. These are resistant to drilling, picking and have profiles that can’t be easily reproduced.
I hope this information is useful.