These are some of the tools I frequently use to troubleshoot patron questions, or refer the patron to for a quick introduction to a jurisdiction or topic.
Lexis and Westlaw are completely hit and miss for non-US material.
In general, they're OK for international law, although often there are more user-friendly ways of getting the information. For national law, some countries have very good coverage, e.g. UK coverage is close to comprehensive on Westlaw. For a good part of the world, though, there will be little to no material, with the average being a few journals and news sources, and a "Doing Business in..." type publication. The only way to be sure is to go in and look.
Here are a few pointers for using them:
1. Not all foreign content has moved onto the WestlawNext platform, and none at all has moved to Lexis Advance yet. You will have to revert back to old Lexis, and since they killed Westlaw Classic in July 2014, some content may still be in limbo and not findable for the time being.
2. Check both platforms, because coverage for a country is dependent on which vendor bought out which publishers. You may have to go to Lexis for case law and Westlaw for journals, or Lexis might have bought all the publishers, leaving Westlaw with nothing for that jurisdiction.
3. We have stand-alone Lexis and Westlaw databases with additional content for some countries: Canada (Lexis Quicklaw), China (Lexis China and Westlaw China) and France (Lexis JurisClasseur). None of these can be accessed within the Lexis/Westlaw for Law Schools platforms. Use the e-resources A-Z list for quick access instead.