I personally prefer the latter, because otherwise you break circular resolution (that is, if you reverse-resolve an IP address to a fully-qualified domain name (FQDN), then forward-resolve the FQDN, you get a different IP address).
Circular resolution the other way is unreliable, because many names can resolve to one address; but since an address can only PTR to one name, it's often held that that name should at least resolve back to the starting address. Sometimes, odd things can happen if this is not so.
The need to get this right is confirmed by RFC1912, which says
Make sure your PTR and A records match. For every IP address, there
should be a matching PTR record in the in-addr.arpa domain. If a host
is multi-homed, (more than one IP address) make sure that all IP
addresses have a corresponding PTR record (not just the first one).
Failure to have matching PTR and A records can cause loss of Internet
services similar to not being registered in the DNS at all.