The ASIC miner companies are about as reliable as a rusty Yugo. Don't invest any money you aren't willing to lose. I placed an order for a Butterfly labs box in December. They still haven't shipped. I also ordered a batch 1 Avalon Asic that has shipped, arrived, and has paid for itself. The day that box broke even I canceled my Butterfly order. I subsequently ordered two more of the Avalon asics in Batch 2 and am expecting delivery within the next 3-5 weeks. The batch 1 Avalon will have paid for the batch 2 boxes by the time they arrive. The batch 3 avalons are significantly more expensive, and violate my risk/return time horizon. I am not purchasing any at this time.
My long term approach is to cash out as soon as possible to pay for the mining hardware. After that, I let BTC accumulate. 1/3 goes to my fund for whatever I want to play with, 1/3 to tangible physical precious metals (coinabul.com) and 1/3 to long term savings. Of my long term savings, a subset is conservatively invested at BtcJam.com. The rest is in a paper wallet.
The pay-for-the-hardware-first approach places me you in the gambler's paradise. That is the sweet spot where you are playing with the house's money and not your own. The disadvantage of this that I've sold 50+ Btc from GPU mining at exchange rates that were grossly lower than what they are today. It happens.
You might also consider investing in AsicMiner shares. Just a thought. That adds a whole other dynamic of risk, since you have people involved.