as there is no definite right or wrong answer to this question, here are a few things to consider:
1) Salary: Should be SSCO > OCC > SKP
2) Hours: Should be SSCO > OCC > SKP, where the >/< should be inserted depending on what you prefer. You definitely work more hours at SSCO
3) Global impact/footprint: SKP > OCC/SSCO while SKP is globally present and growing, the others are rather irrelevant on a global scale
4) Exit Options: No real knowledge here, but might be interesting to consider
5) People: It sounds so lame, but in the end it should come down to where you liked the people more, as you will spend a massive amount of time with them.
Let us know how you decided :-)