This post from Alexandrina Garcia-Verdin, better known in the community as AGV, highlights some of the benefits of the new Google Apps Script V8 runtime including succinct syntax and data processing operations:
Image source: Google
Source: Apps Script’s new V8 runtime | Google Cloud Blog
This page describes the new features enabled by V8 and how you can enable V8 for use in your scripts. Migrating scripts to V8 describes steps for migrating existing scripts to use the V8 runtime.
Source: V8 Runtime Overview | Apps Script | Google Developers