DHCP is easier to setup a bunch of computers because you don't have to worry about which has which IP address. Static can sometimes be better, especially with a lot of network traffic, because you can use port forwarding to prioritize certain traffic on those ports to the static IP, but port forwarding doesn't work with DHCP (at least to my knowledge, because you won't know where to forward to). You can also do both by limiting the DHCP reserved addresses to a certain range, I use 100-199 for that, even though I'm sure I'll never have 100 computers connected.