Using the given s[ecs, you'll find that the SP 35 has more gh/s than the AntMiner S4, even if you multiplied the s4's by three the SP 35 gives you a much greater profit. Here check it out, (this uses a 26% increment in difficulty per month, with 13 being the average for every 2 weeks.)
https://tradeblock.com/mining/a/1545a442ce
The thing is though, you can't make an ROI. The network is too based on large-farms, those that have cheap access and plenty of starting money to purchase large volumes of goods. Hence why the companies sell cheaper if you buy more. Because they know that this is how it works, and also allows them to sell to re-sellers and the large farms.. It's how the system works.

Until someone figures out a cheap and powerful rig that is only available at 1 per costumer.. Us single-home miners are stuck out of the game..

Of course, then with the sp35 comes the big problem.. How do you power a 3500w 208v rig.. Can you even power that from home? Only the A/C, water heating that I can think of require such power..