Read about How Drupal 8 Makes it Easy to Customize Drupal Development
Drupal 8 is the most advance version of Drupal yet, and makes it easier than ever before to customize your Drupal development. Architected for developer productivity, with support for object-oriented support, PHP, Symfony, and more, Drupal 8 makes development simple and fun.
Read the Ultimate Guide to Drupal 8 to get up to speed with all of the exciting new changes for custom Drupal development, including improvements for:
Site Development: Views now in Core, improved entity and field features, more and improved blocks, and more
Back-end Development: A new configuration management system, a completely re-hauled Entity API, improved caching, and new built-in web services features
Front-end Development: HTML5, libraries, accessibility enhancements, new themes and UI elements, and faster performance, to name a few