I'd happily pay $1k installation & $99/month for that level of service.
Seriously, installation is a pittance when you factor in what you actually get.
Hell, even the 50/50 plan is insanely worthwhile (specifically if it is truly without usage caps). Full matched upload and down?
Make running a personal "cloud" service that much more convenient. Or even simply going with any available storage plans.
If they offered this up, I'd probably do the same thing - enjoy gigabit for some time, then drop back to a more reasonable level. I'm sure it'll be difficult justifying gigabit internet speeds at the moment, considering most web services will likely fail to provide anything approach those speeds. Making multiple connections across different services? Max out what five different providers can push to your house, and still have room left to download even more without slowing anything down.
Just to save money and be realistic, an uncapped 50 or 100mbps line at their prices, still leaves me drooling and dreaming. And while I'm dreaming, I'd gladly pay a $500 installation for those speeds and prices. Of course, with a little background check on their company first - if it's hit and miss service with unpredictable yet frequent downtime, no thanks.