Copy data from multiple databases to a central database for reporting and analysis
I have more than 8 databases and all are in a SQL Server environment. I need to extract data from specific tables (more than 50 tables) of each database and dump into a central database for reporting and analysis purposes (a one way transfer).
Table structures are the same in all databases.

REPLICATION : If the objects (tables) you are replicating are not undergoing frequent schema changes then you can use many-to-one replication using T-Rep (this is a very thorough answer that I wrote with scripts and end result), provided you can slightly modify your table schema. This will give you a near-to-realtime data transfer to your central server.
SSIS : If you dont need a near-to-realtime data transfer, then you can look into SSIS - Incremental load using Lookup transform as described in Updating Rows in Incremental Loads – Level 4 of the Stairway to Integration Services. ALso, refer to this excellent series : Stairway to Integration Services for more details. Alternatively, you can test out  Change Data Capture (SSIS) (as @srutzky suggested).