Abhi,
Few key points. SLT and RDA are two standalone options for real-time replication of data into SAP HANA and SAP BW respectively
SLT is only relevant in an SAP HANA landscapte and RDA ( real-time data acquisition) is applicable only in BW scenario without HANA.
Please let me know if you have additional question with specific landscape details so that I can share my experience in context to your environment, if I have any.
Hope this helps!