We in house test all our code using a few thousands unit tests daily with multiple versions of jvm from Sun/Oracle: Java 6 32 and 64 bits, Java 7 32 and 64 bit, Java 8 32 and 64 bit. Your choice of jvm version is a personal decision. Although some of our developers use the IBM clone with eclipse, it is not part of our routine testing procedure. My personal preference is the Oracle Java 8 64 bit. We need 64 bit to process a large amount of data. We prefer Java 8 because it is a much more mature product with history esp. amid-st the infamous security patches and testing/release policy from Oracle lately.