From a forward looking perspective, reporting for PPM 8.0 is supposed to be based on Business Objects Enterprise XI 3.0, with the out of the box reports provided through WEBi. You might want to factor this into your decision making.
Hi, We are using SSRS. We manually load the data from Oracle to SQL Server by means of ETL, and we run reports from there SSRS Report Manager. It has many Pro's and Con's, You have do decide whether you are directly going to hit your Oracle Prod or not for reporting.
If you can directly hit then Crystal Reports is good with Oracle Query, I heard Webfocus is also very good.
If you cannot hit PROD, then SSRS(SQL Server 2005) which is reatively much cheaper software.