One Ethernet WAN port, one Ethernet LAN port, one USB port, and a jack for the power.
While I understand Google's logic behind this, but that's really a deal-killer for me. Even though many of my devices are wireless, I still rely on wired connections when I want a stable, fast and (comparatively) secure connection. Sure, I could pair this up with a second router or switch, but if I'm paying $200 for the damn thing, I'd expect it to cover those basics.
Of course, I was already wary about this just because it is a privacy-destroying Google device (having said that, I'm using Google's DNS servers in my current router so I probably don't have a leg to stand on in that regard). No web-based interface is a stupid idea too; touch-screen based interfaces are too fiddly for my liking. And despite TFAs claim that OnHub is "something you could put anywhere in your house without much embarrassment", I think the thing is hideously ugly. Anyway, in general I don't want people to see the networking infrastructure and a discreet flat box is much easier to tuck away than this round monstrosity. Not to mention the price is outrageous.
I'm really not sure who this device is aimed at. Sure it is easy to setup, but ordinary users are unlikely to drop $200 on a wireless router when they can get one that works fairly well (and really isn't that hard to configure either) for $50 from Walmart (or included "free" with their modem). Meanwhile, everyone else is going to look at OnHub's dearth of features and configurability and then pick up more capable hardware.
In short: No web-interface. Less Ethernet ports than an ASUS. Lame.