While you are waiting for "Off the shelf" ASIC products, or investing fiat for BTC, I'll be accumulating hashpower as it becomes orderable...... all with my original investment.
Let's compare then 6 months, or a year from now....

I'm not waiting for off the shelf products, I just say it's the best method. Off the shelf already exists.. obtain mining equipment from burned out people for far less than retail. It's working fine for me. I may even have a Jupiter soon for half what you paid, delivered at the same time. There are companies who are working on off-the-shelf methods as we speak, and they will leave the others in the dust once they take off.
Yes, if you stay ahead of the average curve you'll do well, but I'm still ahead of you "based on the numbers". By the time you positive-ROI with your 17BTC, I'm already ahead of you (x)BTC * Days.
You have to also understand, I'm spread across holding, trading, selling equipment, mining, etc. We both have our methods. I'm not saying mine is better or I'll be richer.
I'm just saying, you'd be ahead of the curve by default having reinvested the BTC, because the difficulty will reach a loss situation. You'll see 200..300GH going for a couple hundred bucks in just a few months, because Jupiters will be the new Block Erupters.
Unless you plan on living entirely on BTC, in which case you're set for the most part.