Well I just might give in and buy an S2 off amazon... Yes or no?
I understand this is late, but I've been really busy with the farm lately and not keeping up. I bought a used S2, and it has been running on my wire shelving rack for about three months. HOWEVER, I also have several S3s. If I had a choice, I would buy two S3s rather than an S2. Here's why:
1. The S2 puts out about 1.1Th/s consistently. Not bad. However, two S3s will put out 0.9Th/s on less power, and they don't overheat if not overclocked. Two S3s are run off the same capacity power supply as one S2.
2. If you're concerned about reliability (every minute you're down you're losing money), then more smaller units (to a certain degree) producing nearly the same volume is better.
3. I live on Kaua'i Island in Hawai'i. My average indoor temp in winter is 80F. The S2 began to overheat immediately upon firing it up on its arrival. See following for how we had to handle it. Bottom line...S2s are notorious for overheating.
We had to (1) remove the cover, (2) add two case fans blowing into the case from the psu side; we removed the virtually useless magnetic drive fan on the internal psu, placing the case fan over the opening where it used to be; the other is at the front side of the frame, blowing into the blade cavity (Blade 10 side), and (3) add a floor fan blowing into the case from the other (Board 1) side. The case fans run off the psu. It is now stable...although fairly noisy (also more so than two S3s).
My feeling is that the psu should never be in the same case as the blades. It's just too much heat energy radiating back and forth between the psu cavity and the blade cavity at #10, and the thin sheet metal barrier isn't sufficient to shield one from the other. Once we fixed the blades overheating (by removing the case and adding the floor fan), the psu would then fail after a few minutes, but this was fixed by the case fan mods.
Dunno if that's any help.