Yes, I suppose the Ethernet is useful. But it doesn't seem worth sacrificing everything else for. Why not just get a USB or Thunderbolt Ethernet adapter?
"Oh, you want to hook your Firewire drives up to it? That's another adapter. Oh, you want to play or burn CD's? You need to get an external drive then. You want to use your old Magsafe power bricks? Sorry, we changed the connector. You want to lock up the computer while it's at your desk? Sorry, there's no Kensington slot anymore."
At which point the SSD and Retina display sound nice, but that other stuff seems like it's going to a pain in the neck on a daily basis.
Apple tend to deprecate and remove stuff often and quickly. The PC world and Microsoft don't. For those of us who like living on the cutting edge, we're fine with it, but it's not really for everyone.
Remember when the iMac was the first USB-only computer, and had no floppy drive? Both were really unpopular at the time.
(Lack of Kensington is stupid though, I'll agree on that.)
Huh, I hadn't seen the Thunderbolt ones. The USB ones are notorious for not really working (they seem to have driver issues). Hopefully the Thunderbolt ones are better?
I'd second the thunderbolt recommendation but I would question the concerns about USB – until upgrading to Thunderbolt, I had no problems with daily heavy usage (along with several coworkers). The main drawback is that the USB devices can't go over 100Mb.
At which point the SSD and Retina display sound nice, but that other stuff seems like it's going to a pain in the neck on a daily basis.