Are you keeping the networks the same?
Are you using vCenter?
Are you registering the Hosts with the FQDN?
Is DNS changing?
Local Storage or Shared Storage?
if its ESXi Standalone on Local Storage, you should be fine with the exception of if the networks are changing. Different subnet? if so the VM IPs will need to change the, vMotion Network, Management Network, External/Internal DNS and Routing, IP conflicts sorted out. Just have the New IP Scheme ready to implement. Are you moving the switches/router too?
There's a good bit to have ready for any physical site location change and it's different for every environment. Sorry if this is too vague.