I do know my s5's have never found a bitcoin block in the year I've owned them.
Now i have a s7 pointed here, hopefully it finds a block for the pool someday.
The reality is that an S7 is expected to find a block every 4.7 years under the current difficulty. Think about that for a second. 4.7 years.
So sadly, no, your S7 is unlikely to hit a block here (or anywhere). And this is a good illustration of why most miners, especially the smaller ones, prefer pools to solo; a small solo miner can hash for months or years without getting any payout at all.
I purchased my first s7 in October and found a block in less than a month, my first and only block. sadly it was mining at anthole
EDIT: Hopefully Phil will do another group buy so I can weed out the antminers with Avalon gear.
Also, I find it odd that all the fear mongering going on over the block size limit debate never seems to touch on the empty blocks being mined. I even had a member of a prominent wallet company defending mining empty blocks. Seems like a lot of people have their own best interest in mind rather than bitcoins best interest. A wise man once said "..since we expect Bitcoin will last a long time, we don't do shit that assumes Bitcoin wont be here tomorrow"