The Zumo 595LM will have a few features not found on the Zumo 590LM as follows:
Garmin Adventurous Routing™: Yes
Streaming Spotify® & Pandora® music/media players: yes
Smart notifications: yes
LiveTrack: yes
Compatible with Smartphone Link: yes
Live traffic and live weather via Smartphone Link app: yes
Rider alerts: yes
Helmet Law notifications: yes
3D Terrain: yes