I think the main reason that causes the excitement is the price point and the vanilla android experience it's so sexy
Interesting that Android's finally become advanced enough that people specifically want the vanilla version. A few years ago it was all about which companies custom version of Android was best, but now a lot of those extras just annoy people. Hopefully it won't be long before the big manufacturers start putting out devices with stock Android, now that the Nexus 4 is such a big seller (or would be if they were available?). According to PDADB the Nexus 4 is the only phone in the world currently running Android 4.2.
Personally I couldn't wait the 2 months plus for a Nexus 4, I've ordered an Optimus 4X which has a lot of similar specs plus removeable battery and SD card slot. I've got a Pebble watch on preorder so also wanted Bluetooth 4.0 for that (which the Nexus has but not many others do).