Since my final year thesis on 'Distributed Valuation of Partial Differential Equations' I have been involved in designing, developing, and evolving distributed systems in software.
More recently I have been working on using and understanding distributed datastores with a variety of data models, including:
Generally I find the following modified Tolstoy quote holds as an observation on distributed systems.
There are no happy distributed systems (let alone datastores). Every distributed system is unhappy in its own way.