Yes, there are apt repos available. Also yum repos (see links and docs at http://www.azulsystems.com/products/zulu/downloads).

On x86, if you can measure performance diffs between same-version OpenJDK/Zulu and OracleJDK, you are probably measuring noise. Zulu is simply a binary build of OpenJDK. As far as we can tell, the performance is identical because the source is the same.