Use the most recent 'EpsonNet MacAssist for OS X.app' to set up and connect to the printer. You don't want to use rendezvous/bonjour. Yes, the printer can use dynamic IP addresses. However, you'll be better off if your router/switch can reserve a specific IP address for the printer after assigning it one. Since the current Macs are gigabit ethernet (and the printer ethernet is only 10/100) you might be tempted to put the printer on a 10/100 port. I keep mine on the 1000 port for the reason that I don't want slow traffic (and slow "10" devices will slow the router, not so much a problem with a switch) and you want to pump as much bandwidth to the printer from the computer as you can. If you have no "10" devices anywhere on the net, this isn't an issue.
Currently, the new printers are all pretty much the same speed under USB 2, Firewire and 100 (or above) enthernet. So assuming your network is reasonably fast without a lot of packet loss or collisions, printing via the network is just fine & dandy. Just be sure the printer ethernet card is one that Epson has sold in the last 12-18 month. Earlier ethernet cards had a lot of problems unless you assigned the card/printer a static IP address.
Using the Epson 'EPSON LFP Remote Panel' all functions and controls of the printer are accessable over the net. I don't need to access the printer via a web browser (although you can) There is no functional difference at this point whether you connect via ethernet or USB/FW although there's no speed benefit either.