I actually have both, a WR703n and WR702n. You are correct, the 703 interface is entirely in Chinese. I copied/pasted the chinese symbols into Google Translate and made it through. However, if you want to play aroud with settings a little more often then I would get the 702. the 702 does not have the 3G modem ability of the 703 and also uses different electronics, so you will not be able to reflash the 702 with a OPenWrt image https://openwrt.org/ and the different hardware is also the reason that you cannot just flash a 703 firmware (available on the TP-Link website) onto a 702.
I agree that using a web interface to comfortably configure the router is something - to my knowlede - no WiFi shield offers, which I find very valuable, particularly if other, less technically inclied people need to interface with a project/device.
The 703 came pre-configured as an AP with DHCP enabled. My project uses the DHCP/Bonjour library and using this router pretty much made it a plug and play solution.
The 702 came pre-configured as an AP as well but oddly enough with DHCP disabled which I changed.
Both units can be configured in client mode which is very similar to bridge mode and makes it very easy to integrate them into an existing network.