OBIA  

1. OBIA is the pre-packaged BI Apps that Oracle has provided for several years. It is the data warehouse based Solution

2. It is based on the Universal data warehouse design with different prebuilt adapters that can connect to various source application to bring the     data into the warehouse

3. It allows consolidating the data from various sources to bring them together

4. It provides a library of metrics that help to measure business

5. It provides set of predefined reports and dashboards

6. OBIA works for multiple sources including E-Business Suite, PeopleSoft, JDE, SAP and FUSION Applications

OTBI

1. It is a real time BI

2. There is no warehouse or ETL process for OTBI

3. It is a Fusion Apps only

4. OTBI leveraging the advanced technologies from both BI platform and ADF to enable the online BI queries against database directly

5. OTBI does not have prebuilt dashboards and reports like OBIA

Note:

Both OTBI and OBIA are available from same metadata repository. Some of the repository objects are shared between OTBI and OBIA. It was designed to allows to have following configuration:

OTBI Only

OBIA Only

OTBI and OBIA coexist 

Both OTBI and OBIA are accessing Fusion Apps via the ADF