Does Subwords work with Mylyn and JDT completion?
No. Subwords deactivate itself as soon as it detects its put on the default content assist list together with Mylyn or JDT's Java completion. Only one of these engines can be used on the default tab.
Can't download any recommendation models. What's wrong?
If your .metadata/.plugins/org.eclipse.recommenders.rcp/ folder stays almost empty either your repository URL is incorrect or your company network requires you to go through an internal proxy. 1.0.0 does not support proxies. A patch for is in progress. See http://www.eclipse.org/forums/index.php/mv/msg/366941/894052/#msg_894052 for details how to patch Recommenders manually and build it using maven tycho.
Can I generate my own models ?
Generally yes but there is yet no API to support for this. To build and provide you own models, you have to (i) provide your own model repository and (ii) provide your own model archives. Models for, for instance, call completion can be generated by yourself by specifying the patterns for you libraries explicitly using BayesianNetwork class in org.eclipse.recommenders.bayes.serialization. Some more documentation about the network structure will follow.