Is it worth upgrading to the premium version of strava, what extras do you get for your money?
They have a free trial....
However, my personal opinion on strava is I will never pay unless they sort out some basic functionality - allowing you to show you a real pace for runs that have stops/slow sections in them (yes, I know of two work arounds, setting a run as a race or remembering to pause your watch for 1 s to trick it into thinking pauses are on when they aren’t, but that just isn’t good enough). Data to me is only as good as its accuracy, and cutting out any time I’m still in a run and inflating my pace accordingly is hardly accurate.
Much discussed here https://support.strava.com/hc/en-us/community/posts/208861027-Feedback-on-Run-Tags-and-Moving-Time-Pace-Calculation#post_22953460
I've been on and off over the years but been on most recently for a few months. I like the breakdown of Heart Rate analysis to allow me to moderate runs to HR as opposed to pace. Garmin connect does this as well but I just don't like the Garmin App.
The more you use it with HR analysis the more it builds a picture of what it calls 'Relative Effort'. So it establishes what is a hard run for you regardless of pace or distance based upon HR and history. Then it compiles this into what are weekly averages for you so it then informs you whether you have really ramped up your training/relative effort or the opposite. This can help you steadily increase mileage etc. Whether this is worth the extra money is a personal choice but it is worth a trial and see if you enjoy the perks.