DMZ is a very bad idea to use in any case.
Basically what DMZ does, is completely disables the router protocol for any ip address and forward all ports from outside to the internal.
And the server can still be within your network and thus be accessible. So any port is open to your server and any unwanted attacks are possible.
Port Forwarding is ALWAYS the way to go. DMZ is usually used for when your router does not support the kind of traffic, or there's a second router behind and your router doesn't bridge or for when you quickly need to test if the router is causing any problems.
But remember, you can always place your server outside of the other network if you setup your network correctly using VLAN's (if your router supports such).