There are various retention systems that provide a secure and comfortable fit, namely: laces; Velcro; Techlace (lace and Velcro mix); ratchet, and BOA dials, each of which have their benefits. In some cases, two of these systems can be combined for a more personal and tailored fit.
For cross-country focused shoes we like to see a ratchet or BOA-style closure, but for trail and enduro we like the simplicity of traditional laces.