I would go with squishymango's advice. Get a BB from craigslist, ebay, etc that'll hold you over for a few months. You'll get a taste of the BB OS and then you'll be a pro at using your new Onyx.
The thing is, something better is always just around the corner. The Onyx will come out, and the rumor mill will already be discussing the next great device that blows the Onyx out of the water, and will hit stores in just a few months.
My thinking, unless that device right around the corner features a game changer for you and you have your needs covered for the interim, why wait?