In this review, Nepotismia have a look at the Server version of 6.06 from an administrators perspective.
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In general, I found Ubuntu 6.06 Server to provide a good range of software for use on production machines. The various packages generally seemed to be in a much more ready-to-run state than I've found for comparable Linux Enterprise distributions; there's certainly much less messing around to get the system going.
All that remains to be seen now is whether companies such as Oracle will come to the table, and certify the system for use with their software. I'm sure such an event would then provide the answer to the wishes of many a system administrator; to have a homogenous network of only Debian-based servers, without the need for one or two Redhat or SuSE servers purely to handle Oracle.