yes i can give info on them.
The sp20's I ran up to 12 at a time.
The s-5s' I ran 3 at a time.
The s-4's I never owned and have been plagued with psu issues that is why I never purchased them.
The sp 20's scale watts per gh and hash rate. they can clock as low as 800gh and do .45 to .47 watts a gh. they can scale up to .7 watts a gh at 1600gh.
Do Not for 1 minute consider them over 1600ghThey can only be purchased used without warranty they stack well I have stacked them 6 high with 0 issues. they have a really good gui .
The s-5 runs pretty flat .50-.52 watts per gh 900gh to 1300gh to go to 1250gh -1300gh you need quailty psu's with a little cooling help
the gui is not as good.
The s-5 can be purchased new with a warranty .
If I were you I would get some of both as they work well together.
I would want to pay 375-385 max for an s-5
I would want to pay 400 -425 for an sp20.
I would not want and s4
Do you have any psu's on hand
LASTLY what is your power cost per kwatt. 10 cents or more do not do it.
my sp20 review
https://bitcointalk.org/index.php?topic=872014.0