> Even a resonator often isn't good enough

The range is better than it used to be. For example Murata have
several tight products. Not quite crystals but in the 100's ppm
(0.05% typical)

http://www.murata.com/articles/ta0541.pdf

Meeting the demand for USB etc

Factors for the OP to consider include cost (and cost benefit), size,
assembly, long-term (vs initial accuracy), stability and availability

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