Crashlytics' / Fabric has a daily email which gives you a sense of recent crashes, and also some basic stats.  It's useful, but they don't seem to consider that there can be a fair amount of day-to-day variance and attempt to smooth that out and give you a sense of real trends. Instead, everything is about yesterday's change:

• Day N:
• New sessions up 20%!
• Your app is on fire!
• Seek investment immediately!

• Day N+1:
• New sessions down 15%!
• Your app is beginning to stagnate!
• Oh noes!