Considering performance into account, which is the best option to use for getting results from DB table in the activity. Obj-Browse or pxRetrieveData (OOTB activity)?
I recommend retrieving the results from the DB table using the Data Page.
From a best practice standpoint, Obj-Browse is not recommended unless you can’t achieve through the alternative approaches. Please find the below link for your reference
pxRetrieveReportData - Executes more number rules, but provide more flexibility like joins and association
obj-browse - light operation, but works for simple scenarios (less flexibility) as a simple requirement to pull data from the table and it fetches the results quickly
so if you have a simple requirement to pull data from the table then you can go with an obj-browse method and it fetches the results quickly.