Difference between OBIEE and Siebel Analytics:

Siebel Analytics:

Siebel Analytics is a Data Warehouse that were coming out of the
box with pre configured ETL mappings from source (siebel crm) to
target (DW)with its reporting component DASHBOARD (Siebel
Answers, Disconnect analytics and Administration tool to build
dashboard reports => .rpd file)

OBIEE:

What is OBIEE

Prebuild Informatica ETL mappings are only comes if you are buying analytics application version 7x and up and the latest version is 7.9.3 with OBIEE server. Licensing fees for for informatica is included with your analytics application.

OBIEE server can be implement and run dashboard report from a physical database (DW, OLAP). You can use any ETL tool (OWB, Informatica, SSIS etc) and design and develop your own ETL mappings and load your DW.
 I think OWB comes free with Oracle 10g enterprise edition

OBIEE stands for Oracle Business Intelligence Enterprise edition
(Formerly known as siebel analytics).

OBE EE is rebundled Siebel Analytics. It is much better than Discoverer (now called OBI SE).

What is the difference between SE, SE One and EE??

SE - Primarily contains Discoverer, Oracle Reports etc. This is what Oracle had before the acquisition of Siebel and Hyperion. I would recommend not to look at SE as an option unless you have made significant investments on this before

SE1 - It primarily contains components like Oracle Answers, Dashboards, BI Publisher, Oracle DB SE1 and OWB. The reporting software for SE1 and EE are the same. But SE1 contains other components like DB SE1 and OWB. Also, it has licensing restrictions like you cannot use delivers, disconnected analytics etc and also you cannot license it for more than 50 users. So, if your requirement is satisfied alone by using Answers, Dashboards etc then you can go with SE1. But its recommended you go with EE if you have plans of adding more licenses in future that would exceed 50. Remember, you cannot schedule any reports using SE1.

EE Plus - It is the full BI software. It also contains some Hyperion components. Always start with EE plus. If you feel it is not affordable or if you feel you have no plans of expanding then go to SE1.

So a long story cut short, decide upon SE1 or EE based on what your requirements are. If you have experience in discoverer, i would still recommend to go with SE1 or EE not because Discoverer is inferior or so, but because that’s where more development is happening

When Oracle Corp. has acquired Siebel System and decided to make
siebel analytics their flagship analytic engine and renamed it
OBIEE (obiee server + ETL engine+ Reporting). Now this product
is coming with preconfigured ETL mappings and DW schema
available for Siebel CRM, Oracle E Business Suite (Financials,
HR etc.), JD Edwards, and SAP.

So keep in mind OBIEE is a complete Data Warehouse technology
(server+application+ETL+report) where Business Object (BO) is
reporting component which is one of the best reporting product
available in the market.

BO can also access and deliver reports that can be build based on
OBIEE DW tables