ImDevil,

Replication are very important for Reporting and Warm-standy purposes. In real time scenerio, you have to be good extensively in Transactional Replication and Merge Replication

a) Transactional Replication: We use this type when there are less subscribers and data has to replicated in transaction basis. You will come with issue like network disconnectivity,jobs are failing, Performance is really bad in publisher.

b) Merge replication: In my current project We are using it.  We have 1 central publisher and 15 Subscribers that synchronize on nightly basis. It is big headache when you have to deal with Conflicts and check connectivity and performance of each subscriber.