Why most of the organisation go for ospf even if they are having all cisco devices?

 It's generally easier to configure EIGRP, but in some cases, this protocol is

  less flexible if you want to implement things like Stub and NSSA-like

  routing zones.

OSPF is perhaps the most widely used interior gateway protocol (IGP) in large enterprise networks.

It detects changes in the topology, such as link failures, and converges on a new loop-free routing structure within seconds.

Routers in the same broadcast domain or at each end of a point-to-point telecommunications link form adjacencies when they have detected each other.

This detection occurs when a router identifies itself in a hello OSPF protocol packet.

This is called a two-way state and is the most basic relationship.

The routers in an Ethernet or frame relay network select a designated router (DR) and a backup designated router (BDR) which act as a hub to reduce traffic between routers.

Because of scalability(larger networks), and less processor intensive, less cpu utilisation and also, standard. So, that if in future we may have different devices and ospf is already running in advance.