A search using the keyword "OSTIA" in the search box on the main PO.DAAC landing page turns up two versions of the data set: https://podaac.jpl.nasa.gov/datasetlist?search=OSTIA
Reading the descriptions it seems the main difference is the exclusion of daytime SST from the UKMO product, though the suite of satellite sensors that goes into each is rather different overall and the UKMO product also lists in situ data among the sensors.
Can anyone offer any suggestions on the relative merits of the two products?
Thanks,
John Wilkin