Anyway, we will see a long period that network hashrate will not increase like crazy now.
The purpose of your Neptune is to "produce" bitcoins for you. If you can refund that miner and buy more bitcoins (or any close to the amount of bitcoins) that the miner will produce, you have reduced your risk substantially and achieved your end goal faster (getting the bitcoins).
For people that paid 10-12 bitcoins for their order and now can refund and go buy 20 bitcoins, this is a no brainer and a great trade.
3 TH/s in a market that will be 60,000 TH/s by the time you get your miners will take more than 6 months to get your 20 bitcoin. Likely more than a year depending on network growth. It is just the smart thing to do right now. at $400, it is even better. At $250, it is brilliant.