Starting at $0/mo
Rcmmndr is near-realtime, the preference updates or recommender changes will be reflected to the results right away, there is no large pre-computation phase.
Rcmmndr has a clean restful, JSON API. Getting started is easy as well, as soon as you have enough preferences data, you can immediately start giving recommendations to your users using the default settings.
For advanced users who are familiar with Apache Mahout, Rcmmndr enables custom recommender algorithms through its DSL API.
Rcmmndr woks only with numbers. When it looks at your data, it does not have any idea what these numbers are for. Preference data will probably contain your database keys and you can mask or hash them again before sending to Rcmmndr if you desire.