I've built data intensive applications using MVC frameworks (like Symfony/Laravel). I have a new system requirement to build very flexible querying capability based on any number of fields. The ability to create this potentially complex selector dynamically is necessary so, ProcessWire is obviously a great fit for this particular use-case.
The system is effectively a very large (e-commerce style) stock/parts system. Data querying will need to be almost instantaneous. Anyone used ProcessWire where there are lots (millions) of records involved?
Given that each field is stored in its own table, multiple joins on select statements could potentially impair speed when using larger datasets.