From a Pega point of view it should not matter if you use securefile or basicfile for your blob storage.  However, we have seen issues with using securefiles, especially if your table is large and not partitioned.   There are quite a few bugs on earlier versions so I would recommend that you are on Oracle Proprietary information hidden or higher if you want to use securefiles and make sure that you have the latest patch set.   There is an undocumented Oracle parameter _securefiles_concurrency_estimate that you want to set to 50.  The default value is 12.  And you want to be sure to partition your table using a range-hash partition by a date column (such as pxCreateDateTime) + id column (pzInskey).  Do some googling on high buffer busy waits and securefiles for details on the problems.