I have been wondering that myself. I refused to pre-order since I got burned one too many times. Bitmain is good company but when they started pre-order with L1, I had to take a second look. I have S1s S3s and now S4. And it's all good. I only buy now when all the bugs are resolved. Much like PSU problem with S4 first batch. I rather get a working miner after all bugs are corrected.