With 1686TH/s on the network a 350GHs Jupiter will generate 0.7BTC per daily. That would have been an awful investment.
That would give you a ROI of 3-4 months at current exchange rate, that's pretty normal. However, there is no reason the difficulty won't keep on rising and if it rises at a continued 25-30% rate, they'll never make ROI (but neither will anyone buying in September/October unless there is a new generation of ASICs with better performance and energy consumption).