Here's a list of paid vs free features, for those that aren't sure:
Strava Subscription Features – Strava Support
Free version:
Route recording, tracking and sharing for multiple sports
Basic post-workout analysis tools
Social feed/kudos/comments
Limited segment info (you can track your own segment efforts, but not compare to others)
Beacon (this was previously a paid feature that was made free a few years ago)
Paid version:
Route builder
Segment leaderboards and tracking efforts on segments over time
Live segments - so you can get info on your head unit while out riding
Custom training goals
Training plans
More advanced training analytics and tools (relative effort, freshness/fitness over time, more detailed post-ride analysis, power curves/zones, etc)
Heatmaps