OVO Oracle SPI vrs OEM

Hello Everyone, I was hoping some of you might be able to share your real-life experiences in helping me make the right choice for a monitoring solution.

Way before my time the organisation I work for bought OpenView Operations along with the Oracle Smart-Plugin, but it was never really implemented properly or used. Recently the project has been resurrected and we've had a consultant in three times now attempting to successfully install and configure OVO. They haven't managed it yet but I assume we'll eventually get there!

In terms of monitoring Unix, OVO seems the right choice (I double up as the SA too) but I'm wondering what is best for Oracle. To my mind it seems I have three choices:

1) Monitor Oracle using the OVO Oracle SPI. Pro: one console, one tool
2) Monitor Oracle using OEM agent. Does this offer better functionality? Con: 2 tools, 2 consoles.
3) Moniitor Oracle using OEM agent but get SNMP messages set to OVO. Pro: If OEM offers better functonality than SPI I get that but still have only 1 console.

Does anyone out there have any recommendations? Have you/are you using the OVO Oracle SPI? How does it compare to the OEM agent?

Any advice much appreciated

Austin