The Corsair SF1000L wins in 4 out of 9 comparable specs, with 2 ties. Its biggest advantage is SATA Connectors (100% better).
Pure Power 13 M 850W wins in 3 specs (Warranty: 43% better).
Recommendation
Choose SF1000L if you want the best overall performance — especially sata connectors.
Choose Pure Power 13 M 850W if warranty matters more to you.